No, that's not a screenshot from the first Halo. That's Counter-Strike: Global Offensive. Counter-Strike player Itszu went above and beyond in recreating the famous/infamous site of many a brutal fight, tested friendship, and timeless rivalry — most of them in the classic Rooster Teeth series Red vs Blue. Also I guess some people played Halo matches there every once in a while.
I speak, of course, of Blood Gulch. It's pretty much the beloved map to a tee, but with a couple concessions for CSGO — namely, bomb sites and buy zones (which is also the name of my politically charged pop-punk outfit). It looks so spot-on that I Can't Believe It's Not Halo. Itszu explained how they pulled it off:
"All level geometry is hand-done, including brushwork and displacements. Textures have been modified as needed to support Source's unique texture parameters. All scenery (rocks, trees) ported with Wall Worm Model Tools from Gearbox's level assets for Halo: Custom Edition, with hand-done custom collisions to conform to Source's convex requirements. Some textures are heavily modified from the original, and others are entirely new due to differences in texture tech between halo's Blam engine and Source 2013."
And here are some more screenshots:
Very nicely done. You can download the map on CSGO's Steam Workshop.