Rodrigo
Complete all the dungeon missions, including Inferno mission 7, to unlock Rodrigo with only a combat knife in dungeon mode.

Chris Redfield
Complete Inferno mission 6 to unlock Chris Redfield with a Linear Launcher with infinite ammunition in dungeon mode.

Better partner
Win the game to raise your partner level to 4 in arcade mode. Win the game a 2nd time to raise your partner level to 8 in arcade mode.

Secret Report
Collect all the messages in each level to unlock the Secret Report.

Vs. Roach mode
Complete the 1st mission in dungeon mode to unlock Vs. Roach mode.

Panzerfaust EX
Win the game in Vs. Roach mode to unlock the Panzerfaust EX in Vs. Roach Mode with infinite ammunition.