Resident Evil: Outbreak 
  
PS2
  

Hard mode:

  Beat all five scenarios on Easy or Normal. Hard mode can now be purchased for
    2000 points.
Very Hard mode:

  Beat all five scenarios on Hard. Very Hard mode can now be purchased for
3000 points.
Infinite Ammo mode:
Beat all scenarios with 100% completion. Infinite Ammo
  mode can now be purchased for 50,000 points. 
Unlock characters:

  After unlocking the following characters, 
  go to the Collection option and choose Costumes.  You need to buy them
with points.
Bob:
Beat Outbreak level as Mark. Costs 4000.
Danny:
Beat Hellfire level and get Ren's ID Tag. Costs 5000. 
Doctors:

Beat  Hive level as anyone. Costs 6000. 
Fireman:
Beat Hellfire level as anyone. Costs 3500.
Frank:

Beat Decisions, Decisions level on Hard. Costs 8000. 
Gill:
Beat Hellfire level and get Charlie's ID tag. Costs 5000.
Greg:
Beat Decisions, Decisions level on Very Hard. Costs 10,000. 
Monica:
Beat Below Freezing Point level as anyone. Costs
  5000. 
Mr. Color:
Get all special items. Costs 100,000. 
Nurses:
Beat Hive level on Hard. Costs 5000. 
Peter:
Beat Decisions, Decisions level on Hard. Costs
  5000. 
UBCS:

Beat Decisions, Decisions level as anyone. Costs 8000. 
Will:
Beat Outbreak level on Very Hard. Costst 3000.

 

Thanks to Revolution readers Zombie ed, willfred, Chalmers and payton awesome!