Death Wars...Attack of the Clones? lol
I guess the first thing you should do is ask yourself what are you trying to do with your game. Are you trying to make a game that isn't supposed to be realistic or what are you trying to do? After that, narrow the gameplay down so that however it's supposed to go, it's fun. It's not enough to simply drag and drop a million enemies and say I'm done! Put in lights, maybe make enemies follow patrol paths, mix up the enemies so they aren't all the same, stick to the theme (ww2 or sci-fi?), put the enemies in places that make sense, add more entities, make custom entities, the list goes on. Remember that simply killing lots of enemies will quickly get old after a while, especially if the game mechanics are dull (and complains that shooting in FPSC isn't overly fun).
Also no offense, but calling yourself a team is only going to raise expectations, if someone calls themselves a team the game better be half-decent. Honestly this doesn't look like the work of a team (especially when compared to what other "teams" have pulled off, or even just individuals)...
But don't worry, a lot of people here started with little games like this, you just need to work on it more
Unity Engine 2.6 is now available for FREE