@ryzy27, thanks for the feedback! The balance is definitely a pain point. We wished we'd got to a point where we could scale the spawns based on the # of players, but we ran out of time. Consequently you're absolutely right, it is a rough experience single player. We also thought that doing something like clearing the eyes when you die would be in order, because just pausing the spawns definitely isn't enough. If you're at all far (even with multiple players) it's pretty much over when you die the first time. Definitely needs balancing.
On the note of the gamepad, definitely a better experience there! We initially only coded it for the gamepad, but a lot of people weren't able to play the game so we made a WebGL build that had rudimentary keyboard/mouse support. The UI could definitely use some love for the keyboard/mouse players out there.
Thanks again for the awesome feedback.