bought opus magnum recently fun game, I have played exapunks a while back, it's not my cup of tea. I love programming for fun, but the language didn't gel with me. I liked their other games better, opus magnum is definitely in the top 2
Opus Magnum is one of the most polished Zachtronics games IMO. The presentation is great.
Exapunks can be pretty tricky with the distributed nature, which share some similarities with TIS-100. Like Opus Magnum, though, there are no restrictive code size limits, meaning that some puzzles can be solved with brute force masses of code. It's not as bad as Shenzhen I/O where you have to deal both with a tiny MCU and routing.
I think I liked Infinifactory the most because:
1. It had the least overlap with my day-job work.
2. It's somehow more-pleasing to watch a mechanical (albeit simulated) 3D machine do work, contrasted to the flickering playgrounds of Exapunks or Shenzhen IO.
for anyone on the fence about these games: I'll highly recommend Opus Magnum as the starting point. It's a good intro-to-Zachtronics game because every problem can be brute forced if desired - in many of the others, you need to make some clever arrangements and logical leaps to progress, due to very limited playing field sizes.
they are quite unique and very well-made though. if you like sequence-puzzle games but are getting tired of the endless flood of Sokoban-flavored things, give it a try!