I wanted to reply an expanded reply, but my browser nuked it while I was busy in a uni pair. I forgor to backup reply ;-;
So, for the invincibility period feedback, I want to implement, so that you can move out of flying up anytime between 6 ticks (100 ms) after the start up until animation stops when you automatically take control of yourself. Possibly at any point after you get control back (or just between 6 ticks and only to near to when the animation finishes?), give 3-5 sec invincibility period while you flash or flicker. That'd be post-jam ver 0.0.3 (0.1 would be for completely finished first level), I don't use version control btw. The 6 ticks thing is so called "protection from dummy" (защита от дурака in Russian) so that you don't accidentally ram into terrain (if invincibility period not given) or you don't stop too low. Had more to say in expanded reply.
Also, it's rushed because I implemented lives at the last day of gamejam, so I panicked, stressed and (internally) cried, and had to ease myself by not bothering to implement limited lives and said invincibility period since I'm bad with timings due to skill issue at GMS2's event order.
Oh, yeah, about doing great on second run, currently enemies are cheesable by hugging to the right side aka pointblank. I'd like to make it more challenging without making enemy firerate too ridiculous, revenge bullets or just making it unfair/unfun I forgot what was this exact thing's name, it's a bit complicated.
So, one of the days after gamejam I worked on artificial slowdown on boss. Then I promised not to overscope and left the work as is, so I will work on boss animation since the boss moves too choppy rn.
I like giving frequent updates, though asking people for feedback takes time away from them, so I'd need to be careful.
Have to stop expanding due to math logic subject starting now, don't want browser to nuke reply draft, too lazy to back it up