Repton

Repton
Title screen of the game
Game No.	555
Voting	5.00 points, 1 votes
Developer	Dan Thompson, Andy Kaluzniacki
Company	Sirius Software
Release	1983
Platform	Apple II, Atari 400/800, C64
Genre	Shoot'em Up, Space Invaders
Gamemode	Single player
Operation
Media
Language

Description

Spaceship "Armageddon": active and under control...

... or passive and cloaked.

In the game "Repton", the player defends the eponymous planet against hostile invaders, preventing them from establishing a base station there. To do this, the player pilots their spaceship, the "Armageddon" — armed with a laser cannon — across the planet's building-covered surface, pursuing and destroying enemy craft while simultaneously fending off their projectiles. In particular, the player must intervene whenever the enemy attempts to tap into the planet's energy supply, in order to halt this theft, as well as to recover any energy reserves already stolen and feed them back into the grid. Furthermore, should the spaceship suddenly find itself facing overwhelming enemy forces, it can be rendered temporarily invisible and invulnerable simply by the player releasing the joystick.

Backstory

The hostile Quarriors have invaded the planet Repton; they are siphoning energy from the local human colony, constructing a base station — and are prepared to defend their conquest by any means necessary! The only hope for saving this outpost lies in the intervention of the space-glider squadron, led by the flagship "Armageddon". Thus, in response to a distress signal, this military task force sets out — ready to engage the invaders' diverse array of spacecraft and weaponry.

The game's packaging features a dramatic description of this scenario, which reads as follows:

"Code Crimson, do you read me Star Fighter Armageddon?"
"Affirmative Commander. Over."
"This is urgent! The Quarriors have attacked Repton! They're building a base station and draining our power supply. They're guarding Repton with everything they've got. You and your squadron are our last hope!"
"I'm on my way, Commander!"
"Full speed, Star Fighter. Remember, you (Click! Pop! Buzz! ...)
"Commander?! Come in! Commander?"
Will the Armageddon arrive in time to save Repton? Or will the evil Quarriors take over the colony? There's only one way to find out!

Take over the controls of the Star Fighter Armageddon. Besides a laser gun, you are armed with devastating nuke bombs, a radar screen and an energy shield. You'll need them all to stop the Quarriors! You'll be under constant attack from Nova Cruisers and Single Saucers. You've got to avoid the Spye Surveillance Satellites and the deadly Dyne-Beam Shooters. And watch out for the Draynes that are after the Repton power supply. Repton is a battle so realistic, you will be relieved to find out that you are still on earth when it's over!

To Begin:
Plug your joystick into controller port #2. Insert the disk into the disk drive. Type LOAD "SIRIUS",8. Press RETURN. When the screen reads READY, type RUN to be presented with the game demonstration. Press I to leave the demostration. Other information about the game, including keyboard control, will shown at this time. You may press the Space Bar, f5 key or joystick button during the game demonstration or information sequence to begin the game.

Furthermore, the instructions — which can be accessed from the title screen — are prefaced by a brief introduction to the game:

Priority message to any surviving members of the Repton assault squadron-
I fear this comes too late . We are scattered and weak.They were swift.The North was stripped of life in sant days.The south crumbles. Our sole hope is that one of you lives.
There are minelayers which lay destructive devices in your path and dynes that discharge deadly energy beams.
The spye, through not known to attack, is a hazard to navigation. Beware of flying over the base as it is protected by sam-type missiles.
In view of this dire situation, we have released from sirius base the new repton armageddon ship.
Beyond normal weaponry, it carries a sore of newly developed noke bombs. The ship has also been provided with the latest in shield technology.
The ship also contains an energy converter. The energy drayns, which are stealing power from the repton grid, can be stopped if you fly though their energy beams.
You can then return this power to the grid by flying through the power tube. The power can also be converted into nuke bombs if your supply is spent.

The title screen alternates with a short demo of the game.

Upon request, instructions can be displayed — for example, details on the various enemies and their point values.

In "Training Mode", the player's spaceship is invulnerable.

Design

During gameplay, the screen is divided into two sections: The first 18 of the total 24 visible text lines display the segment of the planetary surface containing the player-controlled spaceship, "Armageddon". In this view, the spaceship always remains centered horizontally, while its movements are depicted by scrolling the landscape to the left or right. Conversely, the bottom 6 text lines display game status information as well as an overview of the game world — reminiscent of a radar screen — which allows the player to locate all enemies, including those currently outside the visible screen area. This overview measures 128 × 38 pixels; thus, it is scaled down at a ratio of 1:16 horizontally, but only 1:4 vertically.

All graphical elements of the game are rendered in shades of purple, dark green, and yellow, and are displayed against a black background; the screen background lights up in a multicolored flash only when the player's own spaceship is destroyed or when a nuclear bomb is deployed. Technical details regarding the graphics display can be found in the "Technical Details" section.

The greatest strength of the player's spaceship is its immense firepower.

Detonating a nuclear warhead destroys all enemies currently on the screen.

The enemy "Dynes" generate horizontal barriers that can only be traversed while cloaked.

Sound

Two short, two-part melodies accompany the start of the game and every successfully completed battle against a wave of invaders (see the "Theme" section). Otherwise, the audio output is limited to providing sound effects for gameplay events — such as gunfire, explosions, and warning alerts — using simple noises.

Audio sequence played upon game over.

Hints

The objective of the game is to destroy as many of the invaders on the planet Repton as possible, and — specifically — to thwart their efforts to establish a base station there for as long as possible. This is primarily achieved by using the radar located in the center of the lower half of the screen to locate the invaders remaining in the current level, tracking them down, and destroying them by opening fire.

The spaceship "Armageddon", loaded with captured energy.

Furthermore, the invaders' siphoning of energy reserves must be swiftly halted, and the stolen energy must be fed back into the planet's power grid. To accomplish this, the energy thief must be caught in the act, and the vertical beam — which the thief uses to siphon the energy — must be severed by flying the spaceship "Armageddon" directly through it. Laden with the confiscated loot, the spaceship must then locate and fly through the energy tunnel (center animation in the gallery below). If the player has already expended one or more nuclear bombs by this point, their ammunition stockpile is replenished by one such bomb.

Each time the player completely wipes out a wave of invaders, they are rewarded with a generous bonus (right animation). This bonus is calculated as the sum of three products: the current wave number × 100; the planet's remaining energy reserves (maximum 140) × 5; and the number of building blocks the invaders still require to complete their base station (maximum 80) × 10.

As soon as the intruders have either completed a base station or drained the planet's entire energy reserves, the battle continues beneath the planet's surface. Here, the game world scrolls steadily from right to left as the player flies through a cave system where — protected by numerous anti-aircraft systems — a final boss ultimately awaits. In this area, neither the radar located in the center of the lower screen nor the nuclear bombs are available; furthermore, the spaceship loses its ability to cloak itself and thereby become invulnerable. Flying by sight alone, the player must fend off incoming projectiles while avoiding contact with structures and the rocks lining the cave ceiling, navigating this path until the final adversary is finally within firing range.

Slowly but surely, the invaders are constructing a base station.

Foiling an energy theft and recovering the stolen energy.

Calculating the bonus after each wave of attacks.

Screen Layout

A typical scene from the game.

Controls

The game "Repton" is controlled primarily using a joystick connected to Port 2. Only at the very beginning of the game instructions — presented as an animation accompanied by explanatory text — can be displayed by pressing the I  key; furthermore, pressing the T  key during this phase activates a training mode in which the player's spaceship is invulnerable, allowing the player to focus exclusively on locating and destroying their opponents.

Finally, pressing the fire button starts the game. Now, deflecting the joystick — up, down, left, or right — determines the spaceship's direction of movement, while holding down the fire button fires a continuous stream of projectiles from the spaceship's laser cannon. As soon as the joystick is no longer being manipulated — that is, neither deflected nor having its fire button pressed — the spaceship switches to a "stealth mode", rendering it both invulnerable and invisible to its enemies. Notably, while in this mode, the spaceship can use any remaining momentum to fly directly over the invaders' base station — which is currently under construction — without triggering the anti-aircraft defense systems stationed there.

Provided that the supply of up to 5 atomic bombs has not yet been exhausted, you can drop one by pressing the SPACE  key, thereby destroying all enemies currently visible in the upper section of the screen (see the animation on the right in the gallery within the "Design" section). However, detonating the explosive requires that the spaceship is not currently in stealth mode. Therefore, if you press the space bar while the joystick is inactive and the spaceship is cloaked, the desired explosion will not occur until the joystick is next activated.

Enemies

The following gallery displays all of the invaders' projectiles, along with the point value the player receives for destroying them. Shooting down an anti-aircraft missile is only rewarded during the second phase — specifically, while traversing the underground cavern.

Nova Cruiser 150 Points

Dyne 100 Points

Nova Cruiser 100 Points

Drayn 75 Points

Minelayer 75 Points

Quarrior 60 Points

Spye 25 Points

Missile 10 Points

The various enemies differ not only in their point values ​​but also in their behavior: for instance, the Nova Cruiser shatters — when struck by a player's projectile — into numerous individual Singleships, which must then be combated in turn. The Dyne sporadically emits a horizontal, destructive energy beam (see the animation on the right in the "Design" section), while Drayns tap into the energy supply of the planet Repton using a vertical beam. Minelayers deploy mines at irregular intervals — symbolized by rotating rods — which pose a deadly threat to the player's spaceship. Quarriors are ceaselessly occupied with gathering building materials from the planet's surface to gradually construct a base station. The Spye is largely harmless, though difficult to hit due to its minimal vertical profile. Finally, destroying anti-aircraft missiles is rewarded with points only during the game's final phase — possibly to prevent players from achieving arbitrarily high scores simply by repeatedly flying over the missile-protected base station and shooting down the continuously launching defensive missiles.

Tips

• The key to success is not ceaseless, wild gunfire, but rather a skillful alternation between brief, active phases of combat and passive waiting while in a cloaked state — invisible and impervious to the invaders and their projectiles.
• If you press the space bar while your spaceship is cloaked, the atomic bomb activated by this action will not detonate immediately, but only upon the next activation of the joystick. This can be exploited by gliding — while cloaked and utilizing the momentum from a previous acceleration — into a region particularly densely populated by invaders, and then detonating a previously armed bomb simply by pressing the fire button.
• Dangerous enemies — particularly Dynes — can be safely eliminated by first distancing oneself from them until they are no longer visible within the game world viewport displayed in the upper half of the screen. Subsequently, one flies the spaceship back toward them — maintaining roughly the same altitude at which the enemies are located — while simultaneously moving the ship up and down and continuously holding down the fire button. This creates a dense barrage of projectiles that flies ahead of one's own spaceship; if the joystick is released the instant the enemy comes back into view, these projectiles will home in on their target, while the player remains invisible — and therefore invulnerable.

Solution

Repton possesses no definitive "solution" in which the hostile invaders are permanently eradicated and peace is restored to the planet Repton. If the player manages to evade the numerous anti-aircraft missiles stationed within the underground cavern — where the mission continues following the completion of the enemy base or the depletion of all energy reserves — they will eventually encounter a final boss; however, upon defeating this boss, the game simply restarts, and the battle against the next invasion begins anew.

Detonating the Armageddon bomb

Continuation of the battle underground

Destroying the final boss in their cavern

Map

The above-ground game world spans a width of 2048 pixels (equivalent to 256 screen characters) and loops cyclically as the player flies across it. The high-rises situated on the surface vary from game to game; however, the central elements of the game are always found in the exact same positions. For instance, in the illustration below, the player's spaceship begins on the open area located at the right edge of the map. Slightly to the left of this lies the tunnel, where captured energy can be fed back into the planet's power supply. The large open space situated between the left and central thirds of the illustration serves as the construction site for the invaders' base station.

Example of the planet surface's appearance

The underground lair of the final boss is also 2048 pixels (256 characters) wide. The structures appearing behind the boss match those found at the cave entrance; thus, these too would presumably repeat cyclically if one were able to fly past the enemy.

Example of the final boss's lair

Cheats

On the CSDb, there is a crack by Pugsy featuring a trainer function:

Options for Pugsy's trainer

Internal Data Structures

Knowledge of memory layout and internal game mechanics is helpful for developing custom trainer functions, as well as for analyzing or manipulating the data used by the game. The following table therefore compiles a range of information regarding "Repton."

Adresse	Inhalt	Wertebereich	Bemerkungen
$0082 — $0084	Score	0...999999	Encoded as "packed BCD", little-endian (least significant byte first)
$0088	Displayed energy level	140...0	Slowly adapts to the available amount of energy.
$00AB	Available energy supply	140...0	—
$00AE	Number of remaining atomic bombs	5...0	—
$00AE	Number of remaining player ships (lives)	5...0	—
$00C0	Number of destroyed attack waves	0..99	—
$00C9	Number of blocks built into the invaders' base station	0...80	—

Votes

Voting of the C64-Wiki users (10=the best vote):
5.00 points at 1 vote. You need to be logged in to cast a vote.
Lemon 64	7,5	April 24, 2026 - 40 votes
Ready 64	7,67	April 25, 2026 - 3 voti
Tilt	Graphisme 4/6, Animation 3/6, Bruitage 3/6, Intérêt 4/6	N° 17 (Novembre/Decembre 1984)
Rombach	8	September 1984 - "Verdict 2"

Critics

Stephan64: "Repton is a graphically and technically beautifully crafted shooter from the early days of the C64, featuring a number of amusing additional challenges. Although I usually succumb to the invaders' overwhelming numbers within a short time, given what the developers managed to squeeze out of the multicolor text mode, the game earns 5 points from me."

Shakermaker303: "A nice little old-school shooter from Sirius. The controls feel a bit sluggish, but they definitely make sense later on when there’s a lot of air traffic. It’s just fun to pick up and play for a quick session."

Rombachs C64-Spieleführer: "Despite sharing nearly identical concepts, the Atari game is superior to *Defender* by Interceptor Software and *Guardian*. In the case of Astroblitz, the graphics are even better. In terms of design, *Repton* is the finest of the *Defender*-style games — and also the one with the highest difficulty level. *Astroblitz*, by contrast, is relatively easy to play (Rating: 2)."

Miscellaneous

Cover

Images of the game's cover art can be found on "Moby Games" and "C64Games" (see the "Weblinks" section). Viewed from the perspective of the player — seated at the controls of their spaceship — the cover depicts a battle scene on the surface of Planet Repton, in which the player uses their laser cannon to fend off a winged, malevolent-looking alien and a flying saucer. For potential buyers who might still be undecided after seeing this illustration, a caption appears beneath it: "KILLER GAME."

Video Recording

Video footage of a rather successful playthrough

Theme

The gallery below presents the title theme and the audio sequence played upon the successful completion of a level, transcribed in standard musical notation. For creative reuse, the musical scores are also available as a PDF document (File:Repton Theme PDF.pdf) and in ABC music notation (File:Repton Theme.abc.txt).

Musical score for the title theme, reconstructed by logging all write accesses to the SID.

Musical score for the melody played after completing a level.

Technical Details

Graphics

"Repton" relies exclusively on the multicolor text mode for its on-screen display and completely eschews the use of sprites. Nevertheless, the horizontal scrolling of the gameplay area — spanning raster lines 4 through 147 (corresponding to the first 18 of the total 24 text lines) — does not occur character by character, but rather in increments of 4 pixels. This is implemented by alternating between two groups of four character sets each, where each individual character set is responsible for rendering only a specific range of raster lines:

• If the screen section containing the gameplay is horizontally scrolled by 2 pixels, a character set starting at address $E000 is used for the first 6 text lines; a set starting at $E800 is used for the next 6 lines; and finally, a set starting at $F000 is used for the subsequent 6 lines; the screen memory begins at address $CC00.
• Conversely, in the event of a horizontal shift of 6 pixels, a character set starting at address $A000 is used for the first 6 text lines; a set starting at $A800 is used for the next 6 lines; and finally, a set starting at $B000 is used for the subsequent 6 lines; in this case, the video RAM begins at $8C00.

The final 6 text lines are always reserved for displaying the current score and are never scrolled; For it, two additional, identical character sets exist with the starting addresses $B800 and $F800.

Highscore

Topscore of Stephan64

1. Stephan64 - 16.115 (29.05.2025)
2. Shakermaker303 - 10.950 (04.06.2026)
3. Niemand - 0 (tt.mm.jjjj)

	#2 Shakermaker303		#3 Niemand

Links

• C64Games.de - Game No. 4581
• Gamebase64.com - Game No. 6307
• CSDb - Release No. 165761
• CSDb (All entries — including those for the game "Repton 3", having no relation to "Repton")
• Lemon64 - Game No. 2121
• ready64 - Game No. 482
• Repton at MobyGames

• Universal Videogame List

Magazine

• Tilt short introduction (pp. 90)