Thank you for playing and the thorough feedback.
Yeah the boss was just a bit rushed to where as soon as I finished him, and I dislike that the best route for the player is to sit on the ground and charge bombs for its entirety. I agree with what you said.
Checkpoints will work as real savepoints at some point, they were kind of hammed in as a safety net to not send the player back to the beginning, as it would be much too punishing.
progress being kept on the 'stage' of the boss fight are also something I plan to fix, as it wasn't intentional and I just wanted the boss in the demo even though it's, to my standards, broken. The boss will be a truly restarted sequence in the future.
Ok I'll most likely have multiple keys for switching other than tab in the next demo, as I've already gotten a bit of feedback telling me that it's uncomfortable and hard to get used to.
Thanks for playing, and thanks for the tips and suggestions.