Diablo 2: Lord of Destruction

Gain Quick XP:
While in gameplay press then type:
"Players #" (whithout the quotes, where '#' is an integer 1-.
This makes the program believe that there are more players in
single-player game. In effect the creature generator makes the
creatures far more deadly, but also one can gain more XP.
This makes 'normal' boss monsters even harder to kill than
Diablo himself. I personally recommend using "Players 8" and while
encountering the 'quest' bosses use "Players 1." This will have
the positive effect of not having an extra of 20 creatures
surrounding you.