very well done. Artwork and the music are fantastic and a nice mix of difficulty with the hint option. Only suggestion would be to widen the window of the time bonus.
for story stage 3 massed level 1 ice elephants in the NW to start and then goof off. Had an earth tower covering the entire area which got to stage ten np until the game was eating over 1 gb memory and crashed. buggy to say the least ehehe.
for anyone having issues with the game, the dual gunner needs at least one upgrade right off the bat to be remotely useful. a good beginning combo is a a level 3 dual gun flanked by a level 1 laser. repeat the combo on the second row as well and then get a frost going just right of the laser on the top row. The only aoe weapon sadly is the rocket launcher and well it's a ton of money to really get useful.
omg yeah the two homing missiles (4x and energy) + the pricey lightning gun cycled every 2.96 seconds is just so much fire and forget damage, it's criminal. by level 40 all a boffo does is dodge and pick up cash.
For boss two, practice dodging the shots when he's circling around you... if you cannot dodge 4 or so of those waves and live, no weapon is gonna help. The weapons I used were the lightning gun and the two missiles and just chain cycled them. Ugly level for sure.
Destroyers own in this game as they are by far the best anti air troops around and do a good job against subs. Their main drawback is that they are low on health so in later levels use battle ships as a wall (later on a carrier is ok as well) to shield massed destroyers. For skills, boost fort life first as that gives more score.