Alrighty, this game doesn't need an in-depth play-through in order to see flaws.
Firstly, this game needs sound, it communicates actions made in the game to the player (i.e. cannon fire) and can really help the atmosphere of the game, it's dead silent, which is already a massive turnoff.
Then, the actual game itself, is nothing, you fire a cannon, the ball bounces, that seems to be all, I tried a few angles, never got to the white wall, but what's the purpose. There's no reason to fire the cannon, no story or explanation as to why you're a cannon and firing at a wall.
Furthermore, where's the power meter? where is the indication that the cannon will fire the ball further? usually that's expected in firing games, especially cannon games. e.g. raft wars.
Though the friction from the ground is nice, the game is smooth and ain't that bad. Great job on that part, helped make the game somewhat more comfortable, but yeah, if you plan on fixing it, there where I can see problems.