Yes most weapons have a secondary mode. The sniper rifles, this activates the scope, the knife is also the most stealthy weapon. If you sneak up behind someone with the knife and slit their throat, they will make no sound....the Sten is also quite a powerful weapon. I carried this alot in the early going and switched to the para-snipe rifle later on. For in close I switched between the Sten and the Thompson when I had ammo. I really enjoy playing this game. I am an American but for some reason in multi-player, I would rather be a Nazi. Mabee cause they had better looking uniforms ??
Anyway, have fun. Good luck....you will need plenty of it later....trust me....