Heya. This game is awesome! I just only have a little grudge against it, and that's the way that the menus are handled.
I usually swap the keybinds for jumping and looking up to make it easier for me to play on a keyboard. This works fairly well when playing the game. But navigating the menus with these keybinds is difficult. Specifically, Z becomes "move up" in all menus, and Up becomes "move up and select". As mentioned before, my keybinds simply swap Z and the Up arrow key.
I would recommend adding separate keybinds for navigating the menus. This would certainly improve the experience for players who have just changed the keybinds for Player 1 to something unusual.
Otherwise, I pretty much like this game. It at least brings something new to the 'f**k-around-find-out' formula of Syobon Action.
I also find it commendable to see this game being written in Haxe. Not many games are written in unique programming languages.