It's good, but it would be better if you could press up (or w) to jump. I don't mind having space work for jumping too, but the obvious way to go up is to press up. There's no reason it shouldn't work.
You can? I missed that. It still would be nice if it was jump when not in a bubble. I've died several times by trying to slow down falling by holding jump, but hitting it too late and jumping out of a bubble.