Now you're thinking with factories
Infinifactory's middle levels had me a little perplexed -- not just because of the puzzles themselves, but because I still hadn't identified the fundamental "thing" of the game. In SpaceChem, puzzles became ruled by your ability to master concurrency and synchronization tools; in TIS-100, by your resourcefulness in storing and moving data.
It wasn't until the last couple puzzles in Production Zone 2 that it clicked for me. Infinifactory's "thing" is flow control: using pushers and blockers, along with 3D space (and gravity!), to manage the position and timing of each part in fine detail. I'm just now stumbling through the primitive mechanisms of preventing overflow and synchronizing multi-step processes, and it feels like I'm finally learning the game, at last.
I might argue that Infinifactory's earlier puzzles don't stress these lessons enough, but, it's hard to really knock it for that. Even when it was only teaching me how to use various types of block, I was having plenty of fun completing puzzles and pushing the narrative forward.
Progress: Resource Site 338.11