The above video doesn't spoil anything story-wise, but it does show some of the weapons you can unlock in Metal Gear Solid 4.
If that's going to bother you, don't press play. Otherwise, feel free to check out some of the incredible guns (which may or may not belong to The Patriots). We can't figure out if any of these would benefit or hurt our ability to sneak -- we'd probably just lose interest and jump in, guns blazing.
(P.S. – Don't forget you can win a copy of MGS4 signed by Hideo Kojima
[Via PS3 Fanboy