The developers have published many background information about the development of the game. Amongst others, there was a "Making Of" series in the RETURN (issue 21 and 22).

Some basic data:

The game consists of over 11.000 hand-written lines of Assembler.
It contains almost 4.800 lines of scripts that are compiled to another 15.000 lines of Assembler.
For the game graphics the multicolor character mode was used, with a skillful mixture of multicolor and HiRes characters.
The graphics were created in Pro Motion 6.5 with the help of further special converting tools.
The masking of the characters in the game is solved by a Cookie Cutter process that uses the properties of the video chip, that sprites, which are shown behind the graphics, let the graphics also shine through sprites that are actually shown in the front of them.
For the automatic finding of the path, rectangular fields and the information, whether you can go from one field to another, are saved for each room. So only the shortest passage to the next field needs to be calculated.
Due to reasons of memory capacity they abstained from a double buffer, nevertheless, the game runs with a 50 Hz screen update rate.
Save for a few exceptions the code was created on ARM Linux hardware.

The people in the game are drawn as sprites, but not constructed from ordinary sprites but plotted into a semi static multiplexed sprite matrix in real time each frame (17 raster-splits per frame).

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