I was gonna knock it down to 2 because the end part it shit (not being able to look back, yeah I get it, but it's a flawed mechanic) and too much trial and error was involved (enemies at the bottom of blind drops? really?) but the ending was great. So, still 3/5.
Too slow. Hard for all the wrong reasons. It's a vicious cycle of never having enough money and not being able to upgrade and kill monsters... to get money! 2/5 poorly thought out. Have more money given for the harder monsters.