If an application or game is played and there's no sounds at all, even if you've enabled the sounds, it is because you didn't allow your phone to play Warning Tones.
to Toggle the sound on or off, Go to Menu>Profile. Select your
activated profile. Then press
Options>Personalize>Warning
tones> and set to "ON"
But if you want the game/application not to play sounds, then set it to "OFF" and your game/application won't make sound even the sound is enabled in the game/application itself.