I tried multiple times and I think I don't get it, oops xD
The tutorial didn't mention the beat mechanic at all, unless I missed it somehow, but from the description I get that it's a rhythm game.
So I choose one or more creatures, which adds them to the bar above, then press the book and the track plays. Then I click... anywhere? To hit the notes? I time it to the beat and the visuals but get really poor scores, not sure what I'm doing wrong. And not sure what adding more creatures does, they don't seem to get summoned at all, I just get damaged and die eventually.
What am I doing wrong? I'd like to enjoy it, there's clearly a nice concept here!