Quite a good game- love the concept, however i would make the following improvements:
-Have some way to get back to the main menu after starting a game. it's annoying having to reload the page when i want to change game mode
-In some of the levels the spikes were too close together, making gameplay nearly impossible
-Also enable using the arrow to keys to move- much easier!
Despite the critiscm i really do like the game :3