Yes, it's a shooter. Remember "Asteroids" of old? It's similar. The fun and creative thing about this is that you get to make / create your own space ships and aliens.
If the boys are going to play shooters anyway, why not something that's creative as well?
This one is excellent. Great graphics, creativity & logical thinking, a must. As Max, you are drawing things with your magic market that "come to life" - great use of physics & gravity - i.e. drawing a see-saw, standing on one end, drawing a ball that falls on it so you are sent shooting up to the level you need to get to. A sailboat to cross water, etc. etc.
Logic puzzle game, using gravity. You have levels, a ball or balls and some other objects. The goal is to depress a large red button somewhere on the screen. The trick is that it doesn't have to be done with the ball.
Levels increase in difficulty so this one can scale upwards, and there is a "create your own levels" mode.