Bugfixes (Image 1):

There was a bug where the timer that makes the enemies stronger would trigger earlier than intended after re-entering the map. Instead of using an Autoload, I used a normal node and inserted the same code. Then I made a few small adjustments – and that was it. Everything ran without bugs.

Update (Image 2-4):

When you die, you see motivational quotes. The quotes change depending on your score in the round and the level you are playing.