The main issues I've found in his games (at least for Shenzen I/O and TIS-100) is that the difficulty ramps up a lot in the later levels, and there are artificial limitations that are make the game way harder and less fun. For example, the lack of a "swap dat acc" instruction, having just 2 registers at most, among others. You can work around that but the game's idea shouldn't require you to exploit weaknesses of its simulation engine.

I feel like that's the point of the game, is it not? I always thought of Shenzhen I/O as a hacking game, not an engineering game. The best solutions are elegant, but in a kind of fucked up and convoluted way. This, to me, is the appeal, but I can see why it turns some people off.

Have to agree with this. I kept thinking "Instead of playing this, I'd be way better of buying an Arduino and building something real instead. I'd learn a real skill and it would be less unnecessarily difficult on top of that."

Of the various Zachtronics games I've tried, Opus Magnum has been the only one where I haven't felt that the interface and the limitations get in the way of letting me execute the solution.