I loved your game. I have been in a cave working on a game so I don't know what you would consider a known issue with it but everything I played through was really classic and interesting. It was refreshing to see a game like this that felt comfortable to play, regarding the dialog style. You pull off a cool style in the cutscenes very well.
I felt like the audio was a bit overbearing at some point but only in that it sounded like it was playing tracks on tracks on tracks. I would love to see more perhaps short cutscenes for introducing each enemy or even trying to play up the light hearted nature of the player character. Perhaps this could just be little word bubbles (Could be too much, just sort of thinking with my mouth open at this point).
Lastly I think it I would love to see some more knock back on the player when they get hit but that is just sort of reaching for ideas.
I really liked your level designs, they were laid out so that I could figure out there was a solution based on what I had previously just seen but didn't spread it out so much as to make me feel like I might be wasting my time or needlessly backtracking.
The way the Gong Triggers those rising pillars is perfect, it slams into frame like butter, felt so rewarding.
Please keep making this game, I would love to see how it is received. I would be more than happy to spread the word like gangbusters.