Very sweet prototype!
Somehow i missed the whole control scheme, because i was stuck in the second fight, trying to choose a skill for the rogue that had no MP left. After consulting the game page i read theres a back key, but currently its not intuitive at all.
The style itself is really really good and i liked the laughing audience on missed attacks a lot. However, currently it looks pretty chaotic in fights and can be confusing at times. In the first fight i didn't really see the slimes at first and wondered what im fighting. The same goes for HP/MP information. I never really knew what enemy to attack since i didn't know how healthy they are. Another little thing (especially for that easy slime fight) is the fact you have to actively go to the next party member to choose an attack. If an action is chosen, it would be nicer if the game brought you to the next in line by default, just to speed things up once you got a flow.
The class image bug in details was already reported, but i saw it too. In fight number 2 i think i saw that the second skeleton was named "Skeleton2". Since its Godot i'd bet you just took the name of the node. For Plunderground i gave objects with tooltips/displayed names a title attribute, so generic goblins can all be called "Goblin", even if there are hundreds in the scene.
Keep it up, looks promising!