The bottom line...
People have been reviewing this game and pointing out flaws, but the bottom line here is that this game is FUN. So many games, both Flash-based and others, look great - and some even play great - but it is a rarity to find a game that is fun as hell to play over and over. I have played this game all the way through from beginning to end three times in the past three days and I'm about to play it a fourth. Even though I can beat it easily it still rocks to be able to get the triple cannon and rain a hail of fire down on the enemies.
Therefore, the only two suggestions I have are:
1. Make a Zorro Tank 2
2. Include more types of enemies and more levels in the second one!