SpaceChem is awesome, I played it a lot on PC and also now on tablet (it's more playable with mouse, though).
Also worth checking are all other games by Zachronics Industries (maker of SpaceChem)[0] - I particularly liked "The Bureau of Steam Engineering", where the goal is to route steam via pipes, valves, etc. inside a mech to make it fight other mechs.
SpaceChem is awesome, I played it a lot on PC and also now on tablet (it's more playable with mouse, though).
Also worth checking are all other games by Zachronics Industries (maker of SpaceChem)[0] - I particularly liked "The Bureau of Steam Engineering", where the goal is to route steam via pipes, valves, etc. inside a mech to make it fight other mechs.
[0] - http://www.zachtronicsindustries.com/