I really appreciate you articulating your feelings in this way and playing my game! It makes me feel very special haha!
A class system would clash with my risk-reward design philosophy, and possibly make the game too easy, as you have a significant advantage over enemies by default already, and it's practically impossible for them to catch up to you if stamina is conserved well and you don't make any noise and additionally it would less incentivise taking upgrades, as taking on debuffs would simply act as a balance to your class benefits, resulting in less run variety and strategy, though I do a horrible job at explaining this in fairness. I had intended to implement a proper tutorial, but I had a family member pass on the middle of development and time got away on me. Plus the game is probably too difficult for a game jam game; I'm very sorry.
Overall, thank you very much for taking time to play my game and leave feedback! I really appreciate it!