For a nerdy scientist, Gordon Freeman quickly proved himself a capable warrior. Xen creatures couldn’t kill him. The US military couldn’t stop him. Striders couldn’t zap him. Assassins, attack helicopters, explosions, radioactive waste, interdimensional monsters and even an entire army of Combine soldiers couldn’t stand in his way.
In the end, the only thing that could stop Gordon Freeman was his creator. After all he survived, Valve put the fatal, final bullet in his dome by simply never releasing Half-Life 2: Episode 3.