Sven Co-op is a cooperative multiplayer modification for the first-person shooter Half-Life developed by Daniel Fearon. In 2013, Valve allowed the team to publish the mod on Steam as a standalone modification.

###Gameplay
The gameplay of Sven Co-op heavily resembles the same of the original Half-Life, so it is highly recommended to be familiar with its gameplay and to complete its tutorial level. Sven Co-op supports Half-Life’s singleplayer but changes it up a bit to improve upon the cooperative aspect of the game.

The levels of Sven Co-op are divided into missions and are usually separated from each other. Many missions take place on several maps with some of them being fused into one. The objective of most levels is to find an exit or complete a specific task – it is not necessary to kill any enemies whatsoever. The maps are used using a variety of settings, starting with Black Mesa and ending with a modern urban war one.

###Changes in comparison with the original game
There are only 12 changes in the original Half-Life gameplay, yet they do not drastically affect the gameplay. Most of the changes were made to the NPCs and the NPC following system. Now you can take any friendly NPC with you, some of the NPCs will even heal you. Several small changes also affect the enemy behavior, for example, the players can no longer free themselves from the barnacles. A teammate is needed to get you out.