var impact : AnimationClip;
function Start(){

animation.AddClip(impact, "impact");

}

function Update () {
if (Input.GetButton ("Fire1"))
animation.CrossFade("impact"); // Можно использовать ещё и animation.CrossFade(); Можно и с Play, но... Поясняю: Play - анимация без смешивания, а CrossFade - со смешиванием

}

using UnityEngine;
using System.Collections;

public class SidDown : MonoBehaviour {
  public Camera camere;
  public float camPosXyy = -0.1950684f;
  public float camPosYyy = 2.217274f;
  public float camPosZyy = 0.3647461f;
   
  public float camPosXym = -0.1950684f;
  public float camPosYym = 0.687458f;
  public float camPosZym = 0.3647461f;
   
  Vector3 yy;
  Vector3 ym;

  // Use this for initialization
  void Start () {
         yy.y = camPosYyy;
         yy.x = camPosXyy;
         yy.z = camPosZyy;
         ym.y = camPosYym;
  }
  // Update is called once per frame
  void Update () {
   if(Input.GetKeyDown(KeyCode.C))
   {
    camere.transform.localPosition = ym;
   }
   if(Input.GetKeyUp(KeyCode.C))
   {
    camere.transform.localPosition = yy;
   }
  }
}