Leveling feels a little slow. If the game were longer it would start to feel like a slog. Increasing experience gains by roughly twenty percent would tighten it up.
Flamethrower? Rank 99 Fire-rate? Sweet! *saves up and buys* .... Really? You have an /extra/ cooldown on the fastest weapon? What's the point of getting it, then!?
Glowing Ambition I boosts your damage by twenty percent, and lasts three turns. In other words: for the cost of 100% attack damage, you deal 60% attack damage over the duration of the effect.
It's nice to know that the developer spent five seconds thinking that through.
#1. The boss getting through should not equate to an instant loss.
#2. You should re-evaluate your difficulty levels, as they currently force the player to act in a specific way.