Thank you for playing! I'm glad you had fun.
As I mentioned in the description, the values can use some tuning, and the scope of the prototype ended up with a cap on the upgrades, in theory though I would like them to continue with further upgrades. So right now, if you play well enough you can get to a point where you have maxed out the upgrade paths and then you may still lose but it could take a long time running the game until that happens so it appears stable.
Really appreciate you playing the game to completion though!