The bosses feel damn near impossible to beat, if this is a design choice.
Each boss has an 'undertale style' don't get hit before the fight, and because of the engine used, and the fact there's no way to make it easier other then accumilating money and hp, which ups your fragmentation, which there's no real way to get rid of that without blowing more money then you make, the bosses feel like they're designed to make you loose outright.