Quote: "1.- a way to, after killing a certain enemy, I can change clothes with the enemy's. I know this is too difficult but could be simulated so that all enemies in the level would not really see me."
Yeah like Hitman. Only it had to do with range, which might be doable.
Quote: "2.- have two modes for the player to walk: normal mode and "sneak" mode"
I like the 90% invisible thingy in battlefield 2142.
This could be done too using a random call.
Meaning they have a 1 in 10 chance of spotting you.
Both of these requests are similar.
Both are simply setting states of the enemy having less awareness.
As he said, in single player mode it won't matter if the player's character changes its appearance because it is never seen.
A simple HUD can display the clothing the player is wearing at the moment.
I do not think it is impossible, until I try and fail.
I have no time now to try it, and when my current project is finished, FPSC X10 will be out.
Wait until FPSC X10, and I'll give it a go.