I couldn't figure out what I was supposed to be doing. I couldn't tell if I was making progress or not. I couldn't work out the purpose of the enemies/NPCs/whatever they were. I could barely control the character.
things like he cant roll all the way over and sometimes the jump does nothing was frustrating. Work on the actual game play and how it feels
If you really like the roller idea, make it easier and more satisfying to control and make the levels much much much more open with stuff that really takes advantage of the roller concept. Like ramps, conveyor belts, loops, that kind of stuff.
But yeah, first thing you need to do is fix the core gameplay.
I played both versions and I think all of this feedback still applies. the character doesn't move by rolling, he just rolls when he collides with a platform, I'd recommend either disabling the rolling or programming in some kind of roll mechanic, look into 'rotate with force' and have him wobble like a weeble, or just 'rotate by n degrees' and add that as part of the movement code.
In the 2nd version, I couldn't even figure out where I was supposed to be going. The only path I felt I had available to me was to head down and I just fell off the bottom of the level.
In building a platformer, I would really recommend you first build a prototype level, some bits with jumps, some claustrophobic areas, add any major mechanic you plan for the game and see how it plays out. find a problem? iron it out, make the character fun to navigate on his own. Once you have that exactly as you want it, then start building the levels around what is fun to do with the character. Thats what people mean by 'work on the core gameplay'