dm_vat is a deathmatch map for Half-Life 2 Deathmatch.

To install dm_vat, you'll need to place the maps folder in with
(steamdir)/steamapps/common/half-life 2 deathmatch/hl2dm/maps or 
(steamdir)/steamapps/common/half-life 2 deathmatch/hl2dm/download/maps or 
another maps directory in the HL2M folder.

You can find these folder through steam by right clicking on your HL2DM game,
clicking "Properties", going to "Installed Files" and clicking "Browse".

If you have criticism on this map, please leave it in the gamebanana comments.

Thanks, -AnstheRam