Awesome! Arrow keys are very common, just not with the mouse. If you make a mouse game I would just always have WASD. Nice job!
Want to +1 that arrows + mouse was the issue for me too though I still had a lot of fun. For a game with few controls like this I would just do both WASD and arrows and then people can use whichever they prefer. There are people with left-handed mice that would appreciate it!