It's the initial release version of the mod. Please extract the files to the Half Life 2: Episode 2 directory. Don't try to run the map in Garry's Mod as it tends to cause crashes & behaves erratically.
1. Extract the files from the ZIP folder downloaded.
2. The folders, Materials, Models, Sound, Maps, extract them into the "steam\steamapps\common\half-life 2\ep2" folder and then press all positive answers when prompted to overwrite anything.
3. Start up Half Life 2: Episode 2 through steam.
4. Ensure the developer console is enabled (Options -> Controls tab -> Advanced -> Enable Developer Console
5. Press the ` or ~ key depending on your keyboard locale, and then type "map gm_hwndu2" in the console. If you need weapons and the HEV suit, type "sv_cheats 1" followed by "impulse 101" in the console.