Not bad for a beginner, but too problematic
The first level works fine, but is a bit too simple to really be exciting. My recommendation would be to have more factors involved in the game, like a primary weapon for one target and a secondary weapon for another target, so that players will have to stretch a little further.
The second level becomes virtually unplayable due to being overcramped with those missile launchers. It uses too many objects to accomplish too little. My suggestion to improve performance would be to make the graphics simpler to keep the game playable. And to make the level interesting instead of frustrating, possibly you could make it a fast one at a time attack instead of an all-at-once onslaught. What you could have is a whack-a-mole type game where the launchers quickly pop up and must be destroyed before they can do their damage, and then retreat to reload. That would make the screen less cluttered, while making that mission more about speed and perfect timing.