Yeah, not communicating the way the shooting mechanic works more clearly is definitely the biggest issue we're getting feedback on. Basically, the lower your sanity, the more powerful the attack is. The fireballs get larger, and their colour is lighter, but the effect is quite sutble, except for at the extremes. The lack of enemy hurt feedback was an oversight on my part, I naively thought the projectile exploding particles were sufficient, but by the time we got chance to have playtesting outside of the team it was too late to add any more. Early play testing, and planning player feedback during the initial design stages are definitely the big take homes from this one!
Thanks for your feedback, and I'm glad you enjoyed playing! :D