Interesting and fun concept - you're effectively forced to get hit at least somewhat while learning the mechanic. I think a small invincibility window after getting hit would make gameplay more predictable and enjoyable. Overall, nicely done!
Glad you enjoyed it and thanks for the feedback! You're absolutely right, it doesn't quite feel consistent or fair due to the way enemy spawns are handled. Something like i-frames would go a long way towards leveling the playing field.
