iPhone battery life reduced by using it a lot?

Hey guys,

I guess this question has been asked a lot, though I feel this is a more specific thing I'm asking about.

My iPhone 4s is just 2 weeks old and I have to admit that I've used it a lot (email, Internet, some games) since I have it. My battery seems to drop rapidly which wasn't like that in the beginning. I downloaded an app that shows me that at 80 percent I have

153 h standby time
2.5 hours 3G talktime
6.1 2g talktime
2.5 h Internet 3G

And it dropped 20 percent in like the last 1.5 hours and I was barely using it.

I'm having it on 3g(shows 4g with my carrier), brightness on 50% and apps in the background are closed.

Since that doesn't match with what they are saying on apples website AT ALL, might I have a bad battery or is it completely normal?

As I said I've been playing this game a lot recently. Could that have "beaten up" my battery life?

Btw, while writing this post it dropped down 3% and I'm not quite the slow writer.

Thanks a lot.

I know that gaming drains the battery, but what I'm asking is; does it decrease my battery life in a long term when I play a lot? That's how it feels like, like when I'm not playing games but just use safari or check my mails or don't even use it my battery life drops rapidly compared to two weeks ago.