Can I use the rules of Arena underground system as the basis for a retro computer game (for non-commercial use (possible exception of participating in retro games competitions))?
Thank you. It's a pity, of course, but I understand you and I won't make an adaptation :) I just liked the concept of the game, the simplicity of the mechanics (and its implementation), which allows for a wide variety, and potentially interesting gameplay combining puzzles and a plot.
