Need help adding game mechanincs

[MKJ]

Ok so I planning on making a game similar to other frictional titles but I wan to add more gameplay elements and don't know how to such as

- Inputs noise from a connected MIC into the game
- a "fallout 3" style system where you can see what body part is damaged and that affects other mechanics (broken leg=can't run or jump as far/high, bruised arm = can't attack as fast, ect)
- other weapons such as a revolver, knife, ect.
- also since you will be able to change "forms" (human to demon and vice-versa) so i need a way to replace the player character w/ a different model and abbilities

any help at all will be greatly appreciated