playing as a crag, i found that i was grabbing onto walls WAY too often. i suggest making it a little less "sticky". also, the spikes don't make it challenging in the right way. Instead of a matter of skill, it feels more like a matter of how much health do i have. in other words, i was hitting spikes almost all the time simply because i didn't know their exact locations. i also think that you shouldn't become stunned when you fall, it tends to make the obstacles a chore when they are supposed to be fun.
for some reason, if you exit the browser mid-way through a battle, it records any deaths you acquired in the battle, and immediately puts you back into that battle