Not bad...for a beginning
-Your game is challenging, but only because the sudden switch of levels gives you no time to prepare. Build future games around the concept of learning your way around the enemy.
-You left NO instructions in the game, or even in the author comments, making even level 1 less than appealing.
-The blue guy was almost impossible to discern from the black guys; choose a more vibrant color next time, such as red. For that matter, you may want to learn a bit about using animated movie clips to make the characters themselves more interesting.
-A larger, moving game map might help you make the game more interesting. Try adding some obstacles, such as walls or manholes, to add to the challenge.
A good start, but it needs a LOT of work, especially in the art department. Keep working on it.