Nowtun, you should definately study how Metal Gear Solid uses 'sneaking' in their games.
The surface Abe walks on should have an effect on his stealth. If Abe walks through a puddle, the noise it makes is louder, and will be heard by a slig about 15meters away. If Abe runs through a puddle, the noise can be heard by a slig 25meters away. If Abe's sneaks through a puddle, the slig can't hear Abe even when Abe is only 5meters away.
Is this the kind of thing you have in mind?
|