Not developed nearly enough
The idea behind it is pretty great - the idea of a penguin shooting down planes brought some very interesting images to mind. But you haven't developed this concept nearly enough here.
Take, for example, your setting. You've put a penguin in some rolling green hills, rather than in an arctic environment. Some more cold colors would add to the effect, maybe some snowfall?
Then we get to the game itself. It looks like something from a beginner-level tutorial; absolutely nothing about this game is innovative or unique. It's like the simplest shoot-em-downs from the 80s, but with a penguin instead of whatever is normally on the ground. Your mechanics concept needs a lot of work; you could go a lot of ways with this and end up with a truly unique (and very enjoyable) game.
Nice start, but you have a long way to go.