OK, So I'm still playing the single player version. I've already beaten the game once and unlocked a few weapons and tweaks for the next time. I started my next go around and am attempting to beat the game again when I seem to have found a game-ending glitch.
During "Path of Light" I had enabled the M32-Warhammer gun. I was allowed to select it early in the chapter. I then proceeded to bring down the golden archs and when the one breaks and you're hanging from it you have to shoot the eye out with your pistol. I'm not sure why, but I don't have a pistol available. I only have the warhammer, which it will not allow me to select. I tried to reload from last checkpoint so I could attempt to find a pistol but the last checkpoint just starts me right there, hanging from the arch. I can't move, die, or anything. I can only hang there with nothing to do. It was upsetting enough to make me come on here and write this out.
Is there any hope? Do I have to start all over? Is there any way to revert to an earlier checkpoint?
I forgot to mention that I have purchased and tried every weapon I could imagine might work, but I am not allowed to equip any weapons because I get the "This item cannot be enabled while Drake is performing this action" message.