More funny than the original solo playing. You can fight against survivors, to kill all 4, spawning and respawning as bosses (boomers, smokers, hunters and tank) usual do in the game.
I defeated the survivivors at the end of the stage as the 2nd Tank on the map Blood Harvest-Cornfield of versus mode.
Note in the video that survivors, all bots in the game, usually spawn once or twice in a map in a way that obviously can't be done by human players.
That stage was runned in normal level mode for survivors (which of course equals advanced level for infected side).

For more info (how to play versus mode in solo mode) read there:
http://www.gamefaqs.com/boards/genmessage.php?board=93740... (less info)