Alien Breed II in your browser
Insert your Alien Breed II disk images (.adf, Amiga 500 version: disks 1 and 2). Drop them here or choose them below. They are not uploaded anywhere.
Fire (Ctrl / Z or a gamepad button) skips the intro; on the title screen fire starts the game. Without a key the game plays its intro and then its own demo.
Arrows · Ctrl / Z = fire · M map · Space terminal · player 2: I J K L + right Shift · E Original / Enhanced · F full screen · P pause
About this rebuild
Thanks for playing! This preview ends here – the full game will follow.
Alien Breed II: The Horror Continues (Team17, 1993) rebuilt for the browser from the game's own code: the 68000 code on your disks is statically translated to C and WebAssembly with the AREK kit, and the Amiga chipset (bus slots, Copper, Blitter, bitplanes, sprites, Paula) is a model checked against an emulator.
Measured against the original in an emulator (level 1, four 30-second runs with random joystick input): 99.9 % of the pixels match, the sound chip writes match in 97–100 % of the frames, and the game state matches tick by tick for the whole run in one of the four – in the others small CPU timing differences make the runs drift apart after 1–3 seconds. Enhanced draws a wider view from the level map and the game's own drawing, and moves smoothly at your display's rate.
After Start the game boots as it did from floppies: its intro, title, hall of fame and credits take about 1½ minutes and end in a demo that plays itself. Fire (Ctrl / Z or a gamepad button) skips the intro; on the title screen fire starts the game, and level 1 is reached in about 25 seconds.
On the way we found two bugs in the original game: explosion debris can fly through a wall and off the map (the game then reads memory outside the map – harmless on an Amiga), and the sound driver can mix up a sound number (a leftover high byte), which silences a channel. Both are handled without changing how the original plays.
The page contains no game data. The translated code and the start state are encrypted and only your own disks unlock them; the disk images never leave your computer.
Built with the AREK kit.