Half-Life: Invasion mod for Half-Life

The HL Invasion story starts at the end of Half-Life. Remember, you were in a train with the strange G-man … Fortunately, scientists hidden in a subsidiary laboratory with Black Mesa manage to repatriate you there with a space probe, in which you jumped just before the G-man kills you.

Once awoken, you discover this secret laboratory that the government forces haven’t discovered yet. You are watching a teleportation experience, when suddenly overtrained marines invade this hiding place … From this moment, you’ll never be alone … This new trip will lead you into subsidiary areas with Black Mesa where you’ll get more revelations about the government objectives and the world of Xen …

WARNING: If you try to cheat with god, noclip or notarget, the game will crash!
Also, you must know french to understand what most of the NPCs say!