Very cool concept. I loved the rising and lowering balloon while shooting. It kept me active in navigating as well as tracking enemies.
I did end up just staying in the balloon almost the whole time. The few times I venture out I'd end up dying, or the balloon would crash, so I just stayed in the balloon. Maybe a tutorial level where you learn how to fly out, and reenter the balloon without the stakes of dying, would be helpful. And same with the grappling hook. I shot it once at an enemy and then it didn't work after... so I just assumed it was a one use thing.
Overall though. It was a fun play through, and again, the rising balloon concept was awesome.
Cheers!
- D