Metal Gear Solid V: Ground Zeroes is not an FPS. Or rather, it wasn't an FPS, but thanks to an enterprising modder over on Nexus Mods it now sorta is. As you might imagine, converting a third-person stealth-'em-up into a first-person one is something that requires a bit of effort, but it seems to work better than I thought it would, even if I suspect the lack of peripheral awareness will be something of a problem. You can see a video below of the mod in action, or grab it for yourself here.
If you're going to install the mod, remember to backup your game files, and be aware that there are currently a few bugs. Notably: "things vanish when you go near them", Snake has a bit of an invisibility problem, and "pistol animations don't work well like the primary weapon ones". Still, it's an impressive piece of work.
This isn't the first time someone's made a first-person mod for a third-person game. Someone also did the same for Dark Souls, although as there are no guns involved that one didn't work out quite as well. For more modding fun, check out this Ground Zeroes level for Far Cry 4.