It would be hard to sell it for more than $3 when you can get Magic Survival on Android, the same game but with worse graphics, but more levels, hazards, a crapload of more weapons, 20+ classes, etc. etc. for free.
Unfortunately, since the 0.8v patch for Magic Survival, the dev absolutely shit the bed and removed the few things that made the game fun and distinguished in the first place. It's not different from Vampire Survivors now, and at the pace VS's developer is updating the game, VS is way beyond MS now.
There is no way to beat the final boss?
The Reaper isn't a 'final boss' per se, just a convoluted way of putting a hard cap on a run to forcefully end it at 30-minute mark. But the dev does have an intention with this entity, in that eventually the players would kill him and unlock a secret, even if it depends on luck (both literally, as in the in-game stat, and figuratively, because RNG). Oh well, the game does depended on RNGs a lot, so...
Anyway, yeah, the way I see it this game only truly begins after you unlock everything, because before you're playing for the achievements and its unlockables, the next you're playing purely for the challenge and experimentation, and I said this because I've played Magic Survival to absolute hell and back. Currently, it doesn't seem much compared to Magic Survival's arsenal of spells and artifacts selection, but the developer is adding updates and new contents at pretty decent pace. I mentioned how Magic Survival isn't as fun anymore, right? Well, I still find myself coming back to it from time to time, and I can damn well say the same for Vampire Survivors, though I hope they don't do the stupid shit that MS's devs pulled by removing stuff and shattering that delicate balance of fun factor MS used to have.
Right now, the community at large is concerned with the Leaderboards, though I doubt the Codex cared much. I'd prefer the dev add more fun stuff like how the I said above regarding the Reaper. Secret unlockables like what we already know is what elevate this game way above MS in my eyes.