Good, definately can be improved.
This is good, but it can be much better.
Heres some suggestions on how to make it better.
Rather than pressing buttons on keyboard for the weapons make it so you have to draw them, but you have to choose color for certain weapons. And have Multi-Colored weapons that you can draw with more than 1 color, they have speacial propertys, such as a red, and blue shape would make it purple, which could make a bomb in a circle, say you make 1 half red 1 half blue, then they would fuse, if any thing touches it, it will explode in to a circle of missiles. If you make red and yellow, it will make orange, if made, it will make a trampoline like wall or walls. Or you could add a main weapon that swats at enemys.
And finaly have LEVELS, not too many people like going on a constant level killing random things in video games.