I really like the idea. But I felt like it could have been way better if your allies could attack. And since you've released the source, I took the liberty of implementing that myself. And it ended up being so much fun.
Ideally there should be diffculty curve. It starts really difficult right now.
Allies move aswell: they horizontaly oscilate in various speeds and ranges while keeping close to the player character.
You can build your powers quite a lot but it is still suprisingly easy to die.
I coded it quickly so it doesn't quite fit the style of your coding. I want to send you the source. I can either zip now or create a new branch for it on github later