Binary Parasite preview was part of Abbuc Software Contest 2022. It contained only 4 simple levels and very simple graphics, however after the compo deadline it started to grow.:

The final version contains 30+ levels that will test your gaming skills.

Every level has its own password written at the bottom of the screen, next to the level number. You do not need to win the game on one session, most probably you will not be able to do so. You can enter level password in the title screen after pressing OPTION key. First 10 levels are for the beginners and kids, but later the difficulty grows and precisely timed jumps become a must… only devoted players, true gamer legends are able to reach the ending.

Your task is to activate and enter the exit portal in the lower right corner by placing blue bitboxes on the correct combination of buttons.

Each button has its own value (shown in numerical from below the button itself) which is “bitwise ORed” to the final calculated result when activated.

In most of the levels the activated button values are simply bitwise ORed together, however that does not apply in every level. When there is black box with logical operator present in the level then the calculation formula (and eventually the result) depends on how the platforms(containing buttons) connect to the operator. Small tip: when the operator logic is too damn complex you can always try the bruteforce approach and test all the button combinations 😉

Exit portal has also its value, so when this value is reached portal opens.

On the top of all above there are additional numbers visible in the levels. They represent partial goals that need to be reached in order to unlock some bitbox/passage or show some additional platform. Sometimes there are also values that represent traps, so when reached some platform may disappear or blockage appears that disallows the player (or bitbox) to reach the desired position.

Buttons can be activated by placing a bitbox on them or by standing on them with the player character.

Bitboxes can be pushed or pulled by a player, they always move to the direction of player when touched.

Player can push/pull multiple bitboxes at the same time. It is vital to train and understand the pushing/pulling behavior of bitboxes, especially at later levels.

Based on the feedback from players the training mode has been introduced to the game (rev155). Starting from level 10 there is an orbiting projectile trying to hit you. Once it successes the level is restarted. Training mode allows to play levels “on easy mode” without the projectile, it is offered to be activated by getting two shots in a row when standing at starting position (simply by not doing anything but waiting for two kills).

Download

Controls

Joystick:

• Left/Right – move the player left/right
• Fire – jump
• Hold Joy down+Fire – level restart

Keyboard:

• A/D or +/* – move player left/right
• Shift – jump
• Hold Shift+S – level restart
• ESC – level restart

• Shift+ESC – jump to the title screen
• Start+Select+Option – jump to the title screen

Technical overview

Minimum requirements:

• Atari XL/XE with 64kB Ram

Special features:

• full NTSC compatibility (adjusted speed, adjusted colors)
• stereo support (playing music in stereo when dual pokey detected)
• convenient keyboard controls (in case your joystick died e.g. due to your frustration from hard levels)
• in case of using emulator, for proper title screen display enable PAL/NTSC artifacting

Tools used:

• MADS + PSpad
• Altirra
• ZX7 – thanks to XXL for this lovely short and effective decompressor
• Atari FontMaker
• Atari MapMaker 1.1.1 (unreleased version allowing Wysywig DLI level editing)
• SprEd – PMG sprite animation editor
• SwSprEd – character animation editor
• Graph2Font
• RGB graphics format (kudos to R0ger)
• RMT 1.30
• powershell

Numbers:

• 72 kB of level data
• 156 revisions (commits)
• more than 6000 lines of code (excluding the RMT)
• many many many hours of testing and designing the levels