Functionality issue - the A key seems completely unresponsive and is useless unless W is pressed and held first. This creates a diagonal movement, but the square still cannot simply move left with the A key. The arrow keys function fine. Overall a good game. Some polish and fixing of the aforementioned issue or key choice done by the user would be a good addition.
You should totally make a longer version, complete with plot synopsis of how the character is able to jump on the walls, why they lack arms/a face and why a black wall is chasing after the character. For under an hour, this is promising stuff.
Fixed, thank you for the heads up. When I played, I used arrows, so I totally forgot to debug the letter keys. My apologies for the inconvenience.