Macs are crap for gaming, so that's no good for this OP. I'm just waiting for him to come back and complain about a 3-hour post for a gaming session, since he bought a SPro2 for gaming.
The battery indicator is always a rough estimate, yes... the best test is the controlled discharge. Surface 2 with WinRT certainly posts great usable battery life.
Yeah OS X isn't so good if you're big into gaming.
Install Battery Bar Pro. It will tell you what your mW current drain is. This will help you identify if you have other processes running that are sucking power. My system is around 3800 mW which equates to around 8-9 hours. If I play a game or compile some code, I can see the current draw increase and my estimated battery time decrease.
Also, are you playing video from the desktop or from the Metro player? For best life, you want full screen video. Any desktop or charms causes the DWM to kick in rendering stuff. Fullscreen video uses overlay which is more power efficient.
Can't OP also run some app to see the capacity remaining in his battery? I know on OS X this is a feature in System Information, not sure about Windows.