You're the best! Your feedback is amazing!
I'm working in the free mode at the moment and I'm also preparing scene 03 and some extras. Cheats are also planned to be implemented.
The next release will be ready by the end of the month (I hope) and will come with bug fixes and free mode. The checkpoint system you suggested (I had already thought about implementing something similar) and the other things are going to take a little more time because they require testing.
Again, thank you very much for taking the time to test such specific aspects of the game. Being a solo-dev, getting this kind of feedback helps a lot.