Great style, lacked flexibility
So i'm not going to review the game based on it's plot, because obviously, most people play FLASH shooters for the gameplay, and the plot is secondary to everything else. Although I will say I enjoyed how the plot unfolded as you went along.
-The animation, art, and style were top notch. The effects (blood, gunfire, etc...) were well done, and honestly, the visual aspect to this game was what really made it.
-Atmosphere: Unlike most flash games, this one really took time to develop an eerie atmosphere, and elements such as the flashlight only added to the intensity.
-Upgrades: I didn't play long enough to experience the ENTIRE range of the upgrades, but from what I experienced, the upgrades took the edge of an otherwise monotonous game.
-Environment/setting: Although this shooter took a very linear approach, I felt the different routes you could explore helped provide a somewhat "sandbox" feel.
-Diversity in enemies/characters: The introduction of constantly new enemies was refreshing, and I liked how each enemy had a different weakness/strength. It was an element that kept me wanting to play.
-The inability to point my gun in specific direction without jumping around really bugged me. This is a huge drawback, and unfortunately, really lowered the replay value of Breach. I would have liked to see a mouse-controlled aiming interface, or at least the ability to angle the weapon.
-Easy: Although the bosses were pretty difficult, everything about this game was a little too easy. Just AIM, SHOOT, and MOVE ON. Had you implemented a better aiming system, I feel as though you could have added another dimension to the enemies that would have added more challenge.
-Frustrating for the wrong reasons: Although easy, it was challenging in the wrong departments, such as shooting enemies, figuring out where you're supposed to go etc... But again, all this leads back to the aiming factor.
All in all, fun gameplay (although a bit tedious), AMAZING art/animation, unique style, fun plot, and above-average sound effects. Unfortunately, the game had one fundamental flaw which really hurt the experience. I'd definitely like to see a second one, with the ability TO ACTUALLY AIM. Good work though :)