Rat Dungeon fundamentally changes the way that players move in Half-Life 2: Deathmatch. Movement is faster, you jump higher, and techniques such as surfing and airstrafing are a big part of the fast-paced combat. Along with this, weapons have been modified to better suit the game's combat.
The official release build of Rat Dungeon! Install instructions packaged with the game and on this page.
1. Navigate to your Steam library. In the top-left corner, there will be a search bar. Search for Source SDK.
2. Under the 'Tools' category, you will find a list of various Source SDK tools. 'Source SDK Base 2013 Multiplayer' is the one required. Install it.
3. While Source SDK installs, navigate to your steam install directory on your system (usually <main drive>\Program Files (x86)\Steam\steamapps).
4. Under 'steamapps,' locate the 'sourcemods' folder.
5. Unzip the 'rat_dungeon' folder from this install. Drag it into the 'sourcemods' folder.
6. Restart Steam once Source SDK has finished installing for the game to appear in your library. It should appear as Rat Dungeon.
7. The game is now ready to play! Launch it through Steam.