Adheres a little too strictly to formula.
Graphics: Cool glowy neon ships. Kinda dull generic starfield. Shop menu looks cool, but that curve-slider, while cool, is annoying to use repeatedly while window-shopping.
Style: Classic arcade gameplay meets contemporary flash design! Actually, that's a polite way of saying they remade an old Atari game with vector graphics and added a levelling mechanic. Oh well, it still presents itself with pizzaz.
Sound: Understated shooting, check. Meaty explosions when you kill an enemy off-screen, check. Pulse-pumping techno soundtrack? Ch... hey... where'd the music go? Enjoy it while it lasts. It doesn't loop, for some reason.
Violence: Wow, I remember when blowing up spaceships was the most horrific thing a 12-year-old could do with his time.
Interactivity: This is where it goes straight down the tubes. Those stationary turret games offer more diverse gameplay than this. I would have prefered mouse aiming and directional movement controls (including diagonal movement.) But instead we get racecar steering and a straight shot turret.
The problem with this control scheme is, all gameplay essentially boils down to "fly really fast in one direction until all the ships have spawned, then turn 180 degrees and shoot parallel to your exhaust stream." Absolutely any other action you take will either get you rammed by a mine-ship that just spawned or shot up by gunships at point-blank before you can turn and face them.
The tacked on shopping menu neccessary before Armor Games will even consider sponsoring you these days looks pretty, but that novelty curve slider gets old REAL fast, because after the first few levels, everything you could even consider buying is off-screen when you enter the shop. If it just removed bought items from the list, the next thing you're gonna buy would ALWAYS be on top, and the slider could be an interesting but little-used diversion for oggling the stuff you can't buy yet. As it is, the further you advance, the more annoying it is to try and window-shop.
I can't speak to the overall powerup VS enemies balance, because I got tired of shooting my own exhaust smoke after a few levels. Don't get me wrong, I am willing to perform the same stupid task over and over again for hours in order to level up. But the stupid task has to be something fun. Defend Your Castle was fun because the stupid task was fun. Shooting my own exhaust just doesn't do it for me.
Overall: Another pretty flash game brought to its knees by boring gameplay. It sure gives a good first impression, though. Maybe it just wasn't for me. Thanks for making it, though. I look forward to seeing what else you can make.
A game should be challenging, fair, and complex. This game isn't fair if you're flying slow enough to actually see the enemy, and it's not challenging if you're flying fast enough to stay outside the perimeter. It certianly has complex components, but these get simplified when they are abstracted away to tiny dots on your radar 90% of the time.
Maybe I was playing it wrong. But when I tried playing it any other way, I would always lose 90% of my shield in one hit from a mine-ship.