Most of my thoughts have already been commented by others here. Some things I would also point out is that the wall tiles look too much like the ground tiles and can make it look like you can walk places that you can't. I would also say that having a random fail state that has a 5% chance of just ending your run is really not a good idea. It means that any run you start has some chance of literally being impossible to complete for factors completely out of the player's control. The levels are also too big and serve to artificially stretch out the play time, which runs counter to the idea of speed running.