Left 4 Dead

Splitscreen Solo Way

Enter these console commands.

Start versus map with split-screen mode:

ss_map l4d_garage02_lots versus

If your first player in survivors team:

sv_cheats 1; kill [your_nickname]; sv_cheats 0

Use this to start generator with second player:

sv_cheats 1; warp_all_survivors_to_finale; setpos_player 2 6820 5920 20; sv_cheats 0; cmd2 +use

Do not let survivors die during waves, help them teleport away from the crowds of zombies:

bind "g" "sv_cheats 1; warp_all_survivors_here; sv_cheats 0"

Activate generator for second time, then you will become a tank, let survivors kill you, after that truck door will open.
Teleport survivors away from the truck and incap.

Splitscreen Solo Way

Enter this console commands.

Start versus campaign with split-screen mode:

ss_map l4d_garage01_alleys versus

When you infected:

sv_cheats 1; warp_all_survivors_to_checkpoint; warp_all_survivors_to_finale; sv_cheats 0
sv_cheats 1; kill unnamed; sv_cheats 0

When you survivor:

sv_cheats 1; kill [your_nickname]; sv_cheats 0