Pretty fun. The inventory system could use some work though, it felt a bit clunky.
Also, the "blink" bossfight could use some adjustment too, since sometimes he teleports on top of you on accident. It seems that this is sometimes intentional when he does the growing sphere attack, but when he is just jumping like crazy he sometimes teleports onto you and shoots a fireball on the same frame, making it undodgeable.
I did appreciate the scaling of the upgrades, it felt very reasonable and not grindy, I took my time a little and did the quests and had plenty of currency to buy the necessary things plus some QOL.
The only other thing I'd mention is that some of the upgrades were VERY cheap and only gave tiny rewards. This might just be a point of preference, but I prefer when upgrades are bigger and feel like they have more of an impact. The biggest offenders were the heath and passive income one (I forgot what it was called). upgrading for only 1hp when you start with 50 is super underwhelming, especially when boss attacks can deal ~10 hp. Just making it into +10hp or +5hp and having the same effective cost of buying 5 or 10 of the upgrade normally would be better imo, and would make it easier to make decisions on what is worth sending currency on.
But yeah, was fun!