I totally agree. It's frustrating, the game is good, but many little adjustements are needed.
It's like a good guitar who is tuned at 98%.
Two examples :
- the character isn't at the center of the screen, so ennemies from a side are more dangerous than from the other side
- sometimes, when we're on a moving plateform, the caracter don't jump, how ever we push the button. The only solution is to fall.
For the need of inspiration, playdate community is generous, come on a discord, they will really help you if you ask. A boss fight with the ball for example ? A tower to ascend ?
But the idea to keep pushing a project that sale only a little, so don't offer good money back for the time, this is totally understable. No one could blame you for that.