Ghorpm: Did you finish it? It can get insanely difficult past Amiga... I did like it but I was slightly disappointed that in 95% only the graphics were updated and levels got bigger but no change to the gameplay.
I'll draw something soon, stay tuned ;)
Right at the moment I'm playing the SuperNES levels and the Apple II levels. Both seems doable, but I have to replay them several times, because one mistake means death. I also tried the first Amiga level and the difficulty was ok for me. Haven't tried the next ones though. But levels got a lot harder after the regulat 8bit machines for sure.
Overall I like the game, they did a great job on recreating the graphics of the old computers and consoles, also the soundtrack is great and the controls are extemely tight. But I agree with you that they could've added some more new gameplay elements in later levels.