[b]MechWarrior 4 Mercenaries:[/b]
Base Version on 2 Cd"s from Microsoft & FASA Corporation (sometimes called PR0)
[b]Point Release 1:[/b]
Downloadable update by Microsoft and FASA, Brings bug fixes and some new Maps. Most time it is called PR1.
[b]Inner Sphere & Clan Pack:[/b]
These are two buyable Add-On Packs for MechWarrior 4 Mercenaries & Vengeance, and bring more Mechs and Maps to the Game.