this is like one of those flash games where you go underground, do some mining until you can't anymore, and then return to the surface and buy all the upgrades you can, but with the addition of some incredibly light "metroidvania" elements (generous definition). it's better than those, for sure, but it still feels kinda hollow and sorely lacking in intentionality for the majority of the game. there's unique areas with more level design built in with rewards of lots more money or a new power-up, but even those segments aren't all that great. story is nothing, characters are nothing, and most shop purchases are just numerical upgrades as opposed to having cool horizontal progression with optional abilities to bolster the ones along the main path. it's fine.