It's far, far larger than the previous release and deals with alot of issues. All the new stuff is highlighted in red. One of the most notable things is that all bolt weapons now have the Tearing property, making them remarkably more deadly.
Edit: It also addresses some material in the Inquisitor's Handbook.
Edit #2: Some changes I thought I'd highlight.
-Changes have been made to the advances available for all careers.
-Frenzy has changed: it now gives +10 to Weapon Skill, Strength and Toughness but -20 to Ballistic Skill and Intelligence while it lasts. It also makes you immune to fear, stunning and fatigue, though you may not parry, retreat or flee and must use the All-Out Attack action as often as possible.
-Quick Draw applies to pistols, basic weapons and one-handed melee weapons.
-The Accurate quality has changed. Rather than granting +10 to hit it now grants an extra 1d10 damage for every two degrees of success when taking a single shot, up to a maximum of 2d10.
-As mentioned before, all Bolt weapons now have the Tearing property.
-Man-Stopped bullets now increase the Pen of a weapon to 3, rather than adding to it. They can now also be used with hunting rifles.
-Obscura now costs a 10th of what it used to. Time to get addicted.
-Unnatural Aim now applies a +30 bonus, rather than "counts as being made at point blank."
-Rules concerning semi and full-auto fire with Scatter weapons clarified.
-Rules for fleeing from combat made more explicit: you try to move out of their melee range using anything other than disengage and you provoke a Standard Attack of the 1/2 action from them.
-Rules for using pistols in melee combat clarified.
-Fatigue damage from Unarmed Combat changed.
-The Irontalon pistol, while still quite awesome, now has the Primitive quality.