yeah there is. in the mercenaries game, you play as krauser, leon, H.U.N.K., wesker or Ada and complete timed runs on sertain levels to kill as many zombies as possible. if you get a five star rating on all mercenaries stages you unlock a special gun. in the ada game, you go in the part of the game when you first see the regenerators shortly after leon was there (you dont have to worry about those creepy b*stards). and when you beat the ada thing you get another special gun for use in story mode. and after beating the game, if you continue a new game on the same file, you will have all the money and weapons you finished the other game with and the shop guy will sell a special pistol called a "Matilda" and an infinite rocketlauncher for 1,000,000$!
PS: in the mercenary game you can use krausers "steroid arm"!!!