Controls are very floaty and slippery, meaning that often times when you have to jump to an exact block that's beside a fire, it's incredibly easy to make it, only for the character to slide just a couple pixels over and die or fall off the platform. Collectables are meaningless because they aren't so much hard to get as just out of the way, not to mention that the only incentive is an achievement. Everyone's already complained about the checkpoint system and be controllable right after respawning, but the biggest issue by far is that the game is unwin-able at the very end if you push the block off the stage. This reeks of a lack of play testing and is by far the worst offender of the whole ordeal.
In all honesty, with all of this fixed, it would be a very adequate platformer, but such games need a personality or mechanic of their own to stand out amongst the rest of these cookie cutter imitations. Focus on what you want the draw of your game to be and give it a couple elements to compliment that idea. At least that much would give Think Up an identity.