To get the bonuses, you and/or your partner cannot use a continue. The bonuses are located just before you reach the final Boss.
If you choose the parking entrance, keep going until the "security guard" chases you twice. After the second time, look to your right and you will see three to four barrels. One of them has a bonus in it.
If you do well enough, you will get some boxes with items in them before you face the Wheel Of Fate.
Easy game completion
Set the options to 9 credits, 5 fire things, and you must be playing with a light gun. Set the light-gun to auto-fire so that if you hold the trigger you will fire more bullets faster. You can defeat the giant opponent easily. . With the four legged monster, you must have very good aim for the full effect of the bullets from the gun. The final silver Boss is the most difficult. Shoot the blades once and they will disappear, Shoot the lighting once and it will also disappear. When he turns brass just keep shooting and he will eventually die.
Endings
After you see Rogan and G finish talking, you will see Daniel and Lisa talking. Then, Lisa will start walking ahead of Daniel. Daniel will tell her to wait, then he will start talking to himself. They will then walk off. !
After you see Rogan and G finish talking, you will see Daniel and Lisa talking. The same thing will happen, but then you will see a van moving. After that you will see the last zombie driving the car. Lisa will say "Come back you slimy bastards", and start running.
Free play
Successfully complete the game with an "A" rank. Enter the options screen and select "House Of The Dead 3". You can now increase the credits past nine until "Free Play" appears.
Alternately, play well and get better than an "A" rank one or more times during the game at the point where you lose all your credits. This works best in one player mode.
