Hi Valeriy, this game is really cool! It doesn’t feel like a prototype to me, as a Bitsy game it feels like a complete game :)
If you want to make something bigger I’d fancy things like unlocking new classes (one with a keys bonus, one with a guts bonus) and, after reaching the end, unlocking new dungeons with different environments and stories to explore. My favorites rogue-like games are: “1-bit Rogue” and “Cardinal Quest 2” if you like a reference for my favorite unlocking systems.
Wish you all the best of luck!
P.s. The “random feature” is a standard Bitsy feature or is it a hack?