it's pretty good for the first game. I think I've seen somewhere how to make a similar game. Some video course series have a demo project similar to this game.
For me, it was a little bit hard to control the rocket. Even the slightest impact explodes it. You can make some rockets a little less prone to damage. Like instead of exploding after the first hit, some will be just damaged and will explode on the second or third hit. Otherwise, it's pretty good game.