This is probably the best level I've made, or at least the one I'm most pleased with, as it's completely different from basically all the other levels I've played on Super Mario Maker. Which is nice. And also I like the way it looks.
There's four short block-based puzzles, none of which are especially difficult, but which all make use of the various properties of the different block types in slightly different ways.
There are unfortunately a couple of bugs in it (despite me playtesting it for a day and a half). In the second puzzle, if you activate the P-block but then go back through the door which you initially came through, the level becomes impossible to finish. I did edit it once I realised that but because it's impossible to edit levels you've uploaded without deleting them I've just left the bugged one up.
You can also get trapped in the blocks in the final puzzle and also just before the finish line if you try really hard, although those ones you have to be going out of your way to break the level really to end up doing that.