That's an excellent suggestion, and something we should have communicated more clearly! Of course, it came down to time. We've addressed it in a post-jam update, adding a short prompt tutorializing the bounds of the arena before the fight. Hopefully, it's enough to at least introduce the concept before it results in unnecessary damage.
In terms of the attacks, we're going to play with some more clearly discernable windup audio & visual effects for each spell. While they'll still behave the same, players will at least be able to judge what's going to be coming next sooner, making decision-making a bit easier.
Thank you for playing and leaving valuable feedback!