It seems like it, especially if you got more feedback from other people as well :)
A rarity system could be nice to have a bit more variety for sure, but i already like the cards system as it is cause they can be really good boosts to progression compared to the stat points, when i tested i got a railgun which was super handy with the pierce stat upgrades :p
Yeah i suppose the upgrades not working properly could be cause of the save issue but i just gave a heads up in case this was a bug in hope this would help. Cause yah like you said when working on your own game since you know the ins and outs about it you can sometimes not encounter bugs that a regular player could stumble into, thus the importance of feedback XD
But yeah cool progress so far from what i’ve tested / you’ve shown in the logs, and that new UI from the screen looks really nice. Also cool that you plan a campaign mode instead of just the endless mode ^^