I think Infinifactory is mind-blowingly amazing on many levels - an epic triumph of game design. The components are few and simple, but provide enormous combinatorial possibilities. There's a logic-language and aesthetic that emerges, that includes the very things patio11 mentions: input ratios, timing, and pipeline issues. The puzzles are sequenced so that each level is initially shocking, but gradually yields to the player's contemplation and experimentation. I think I've had more pure delight from this game than from any other.

I liked TIS-100 a lot too, and Infinifactory is kind of like a visuospacial, high-production version of it.