Yeah, the limited amount of room to work in SpaceChem, combined with the whole "can't let anything collide" restriction really does make you be a lot more efficient. I never had that same overwhelmed feeling while playing Infinifactory. Some of the later levels require you to really compartmentalize the solution (make four of these out of individual blocks, combine them into two of this other thing, bolt those to the side of a third thing, etc), but you have so much room to stretch out that it never feels quite as harrowing. There were a few times when I was working on a larger level that I'd take a break after finishing a certain section, yet go back two minutes later because I had an idea about how to do the next part.
Oh, that does look interesting, and I'll definitely check that out at some point. I wouldn't say that Infinifactory is really much of a "programming puzzler", though. You actually can rig up some basic logic gates using loose blocks and sensors, but it's really just pushing blocks around and assembling stuff visually. Still, I didn't realize that the current price for Infinifactory was $25. I picked it up during the Summer sale for around $10 right before it left Early Access, and I've gotten more than my money's worth out of it.