Yeeeah, a playable thing! Was waiting for this!
To begin with general remarks, I don't know if the main mechanic is really intuitive. I think it is, but I'm not sure.
The thing is, I knew I was going to be able to reverse the screen before I started to play the game, so I looked for the good control for it. But I feel like a random person might be lost at the 2nd lvl without indications on the controls... I don't know. You should try to get random people to play your game and do some playtesting to know if this is intuitive
Also I feel like the level design might feel "forced" sometime, like, when I was playing the first level, I didn't feel like "Oh I learn that I can jump!" but more like "Oh the game designer want me to learn that I can jump". There is really good things too in your level design (I'll talk about it later), but sometime it made me feel like "forced", like a direct application of game design theories.
Oh and the bottom of your levels feels really weird! (How can I explain that..?)
In level 10 for exemple, when I was on the to left of the screen (after jumping in the first 3 boucing things.), I was thinking that I would fall in the void and died if I jumped. You would need some border, or indication that you can't actually fall and die because you're out of the layout. See what I mean?
I didn't experience any special problem (frame rate or bug) =)
Here's feedbacks on some levels:
I really enjoyed the level 13's puzzle, with the ennemies. The fact that the player have to jump above the first ennemy and then reverse the screen, because else if he reverse the screen before passing the enemy, he would not be able to jump. That was good!
level 16 was really repetitive I think. It's not 4 time the same thing, but almost, it bored me a bit (specially because I died dumbly at the end.). It's long and not really fun. It brokes the rythm a little bit.
The thing in the level 17 that makes the platforms destroyed by the keys is really good! Enjoyed that!
Specially because you used this again in level 18. Which makes the 17th level really useful for the player!
Great to see you used the level design of level 13 again in level 19! This is a clever thing that surprises the player! Good game design here )
level 20 was super cool! Great use of all your mechanics here!
Okay, I think that's all I have to say for now.
It has been fun really! I hope you'll keep working like this on the game! And I hope my feedbacks will be useful :)
Can't wait to see more of this
PS: I attached the stars I got at first try. Thought it might be useful for you to ballance the game