Fun, but a little over the top
***CONTAINS SOME SPOILERS***
I thought the very fast-paced horizontal shooting style was perfect. The boss-fight techniques were perfect (I loved how you defeat Agent White). The difficulty levels were right on target. The shields were a very nice touch...especially when absorbing multiple shots during boss fights. The various layouts of the different stages were pretty cool too...with certain stages being more of a dodge-fest than a shooter-fest. Overall, this game was extremely fun.
While not a technical problem, I was kind of wierded out by the...uh...wierdness of some bosses (for instance...Godzilla, the knockoff of Zelda's Great Deku Tree, the giant Pac-Man...). Dont get me wrong, I loved the boss fight techniques and strategies, but just couldn't help but laugh at the seamingly randomness of the boss art.
Since the entire color pallete was fairly bright, I sometimes found it difficult to distinguish between bright yellow enemy shots, the bright green health-orbs, and the bright background. A little bit of contrasting colors and some darker background colors may have helped there.
What this game is lacking the most is a story...who is the attacking force and what was it's motive? Why was Ice City of such extreme importance? Why is Agent Green so quiet? What the heck was with the abrupt Captain Planet-esque ending?
But overall, it was a very very very fun game.