Named Game of the Year by over 50 publications, Valve's début title blends action and adventure with award-winning technology to create a frighteningly realistic world where players must think to survive. Also includes an exciting multiplayer mode that allows you to play against friends and enemies around the world.
Detailed headcrab. I found the texture on one of TC's packs. I just put the texture into headcrab model. Extract the .rar file into Half-life/valve/models folder.