Igneous

Roll straight forward and jump once. Probably to get you comfortable with the game, but you really don't learn anything...

Even on impossible, this one should be fairly easy. Keep to the right side at first, and after 2 jumps you'll be in the main area of the level. I had the most success with staying somewhat close to the right side of the map, but you really only have to watch out for large magma pools. You'll die immediatly if you fall into one of those, also those flame-like things are deadly.

This one is quite tough already. If you roll straight forward, you'll soon find out that there is a big gap in the bridge and nowhere to jump to. You'll inevitably die. The solution is to make the falling rocks miss the bridge by moving in a zig-zaggy way. That'll make it much more likely to reach the other side. But you still risk being smashed down by one of those falling bricks while jumping over a gap, and not losing your speed with all those small holes in the bridge isn't exactly easy either. You'll pretty much do the same things everywhere in this level, but towards the end you'll most likely slow down so much that you'll be jumping left and right constantly.
Even though you depend heavily on luck it is a lot of fun.

This is the last level. Seriously, I was disappointed when I beat this level on normal (it was insanely easy compared to level2) and then the game was over. Imo the game has a lot more potential for lots of additional cool levels.
Well, it was easy on normal. But it sure wasn't on impossible. 1 hit and you are dead. Those lasers are insanely fast, and your path is blocked by hundreds of boulders. You actually die when the lasers hit anything close to you, but not if the lasers hit you directly. That's important to notice and I don't think I could have finished the game if this wasn't the case.
The first 3 lasers aren't very dodgeable on ground unless you are lucky or play very risky. Instead, you can simply jump over them once you got the timing to do that. Then I would move diagonally to the left, dodge the lasers by moving diagonally to the right and so on, basically zig-zagging again. It's very important that you maintain a high speed (and here I have to say that I really would love to play this with a controller because you can choose your movement direction more precisely with one, pressing left or right only on the keyboard will slow you down, and top/left and top/right usually don't allow you to turn quickly enough), so evade both the lasers and the falling pillars.
Eventually you'll get to the part where the floor collapses as the lasers hit it. Getting to this point can be done very consistently with some practice. Crossing this part imo is one of the hardest things in the game. You'll randomly jump because the floor isn't as flat as it seems, which will often cause you to lose. If you don't lose directly, it will slow you down, which also leads to defeat. Speed is extremely important here, you absolutely want to cross that bridge before it collapses. Going straight forward usually is a bad idea here, to, but in some cases jumping right through the lasers is good.
After you passed this bridge, it'll be easy going for a while. Just dodge and make sure to build lots of speed. You'll need it.
Right before you reach the goal, thousands of bricks will block your way, slow you down and in the mean time you have to evade lasers at an insane frequency. I died around 10 times here, just 2 seconds before finishing the game. I don't know how to get through this area consistently, other than building up speed before you get there and hoping that you are not slowed down too much.