I liked the game. Very clever with the death upgrade system. You can just walk for a bit then kill yourself for an upgrade. Would have been cool to keep a death counter. Make that as a scoring system. Jumping felt a little funny. Think its the case that I expect the character to jump fowards a little more then it does. But I also suck at platformers.
Big take away is this fits the Theme extremely well. Death is an Opportunity, meaning that something pops up, and you should either take it or not. Able to die and having the Opportunity to upgrade or respawn checkpoint to my opinion fits it. I couldn't give theme 5 starts as I couldn't see the game being possible without upgrades. And I see it as you don't have to die, but it'll most likely make your life harder. And once the ghost came in, think that made it impossible to do.
Also, think I found 2 bugs. One I don't know, once the ghosts pop up, they are there till the game is completed. Don't know if that is on purpose or not. And when I got the fireball upgrade, think I also got the slowdown upgrade with it.
But I manage to complete the game and enjoyed, did take me a bit with the spiral.