Thanks for playing.
The rebirth is more or less just a reset. I agree that the game could have had more of a progression system to it, like unlocking more tree tiers and such.
Stacking of curses could be fun, it would probably be quite overpowered, but fun nonetheless.
Thanks for the suggestions, as mentioned in other posts, I'm not actively working on this any more, but there might be some small updates here and there. I've added your suggestion to the backlog.