This is cute! Love all the quack text - though I would've really loved it if the duck made a cute quack every time they jump. Lots of lovely presentation touches, from the dramatic death animations to how you have to jump up from the flomp position when you get hurt - I especially liked that actually. Made it feel like you were jumping back into the game with literal momentum! Always good to see in game tutorials too.
The furthest I got was the bit where you have to use down and jump. Nothing seems to happen and the down arrow + Z and S+K produced different sounds and animations so I'm assuming that's where the game ends.
I was wondering if the animations were playing too fast? The clouds whiz by and the checkpoint save icon goes by super fast. Also it's interesting the camera position the duck so far low to the bottom of the screen. Definitely helps make you feel like a lil duck in a big world though.