I did eventually beat it by intentionally taking no upgrades to avoid becoming a glass cannon. Once you look at the upgrades for a floor you have to pick one (could be nice to let you confirm without picking one if you don't like any of them) but if you avoid the green dot you can just move on after killing the enemies. Every time I took powerups I ended up becoming a glass cannon, but I'm sure there's a fine line between taking powerups and avoiding them that gives this a kind of 'push your luck' feel that is interesting. I liked it overall, good job! One note though: on the last level, the stage extends beyond the viewport, meaning enemies and the player could be stuck offscreen. At least one of my runs ended with me being shot from offscreen on that stage.