Good effort
Nice idea, but far too easy and short.
Meteors could be bigger and take more than one shot, that would increase the difficulty. You could also add extra levels with a variety of enemies perhaps ones that come out of mines etc. You could maybe make exploring the mines more than just rolling over them - destroy basic structure or be stationary on it for a certain amount of time.
The graphics could be improved on. The wheels on the robot look like they are on their side which is a little weird.
Diagonal movement is a must!
Keep up the work and you will have a good game.