Very fun. I quite like this type of game style, and I wish there were more games like it. The art style is insanely satisfying to look at, the pixel and the portraits.
One thing I recommend is some sort of system to protect the XP crystals, so that instead of disappearing, they will clump up into a bigger crystal. Its not a problem right now, but if more weapons and items are planned for the future, it will make the game much more difficult.
I played to the 30 minute mark where what happened was exactly what I expected, which is great. However instead of having the final "enemy" be the same for every map, I suggest having one that is themed around that specific maps style (for example a giant goblin thats faster than you).
Over all a good game, and I cannot wait for it to be developed further.