Good job with the art and polished game play! You've captured that small world theme nicely. The music and effects sound great. I really like the layout and timing of the onscreen hints/tutorial, those work really nicely and have visual appeal without interrupting game play.
You've created a good mechanic with the urgency of keeping the filter going, but the art and sounds really make me want to relax and collect resources at a more casual pace. That o2 meter depletes pretty fast, and I feel at odds with the relaxing atmosphere by having to hustle to keep up.