First off I must say that I really appreciate the extensive feedback. The double picking is unintentional. We found out about it like 4 hours before the deadline. The second bug is also on my radar.
As for the UI, this was my initial idea for it. The available spells in one list and the selected ones in the second list. For the game to work with 7 monsters we initially concluded that we'd have to design 35 spells minimum for the first level (since the pool will be 5 spells less every level) but we were sort of doomed from the start since the scope was so big. The final version of the UI 'works' but overwhelms the players at first sight. So since you brought it up, what do you think of my idea for the improved UI? Would some other aproach be better?
Thanks for playing our game! Hope you try it again when we re-release it.