Indie game storeFree gamesFun gamesHorror games
Game developmentAssetsComics
SalesBundles
Jobs
Tags

I understand the permanent upgrades you spend to unlock. But what does spending to unlock the 3 tiers of weapons do? 

It increases the base level of equipment/weapon you find, but only after the third equipment/weapon you've picked up. We're going to change how it works to make it less confusing.