How to make flips, backflips like in game Backflip madness

Hello, how to create flips, backflips physics like in game Backflip Madness?
Or is there any assets ?

You’ll need to use rotation scripts.

Personally I was too lazy to write one myself but I used this script as reference for my projects:

using UnityEngine;
using System.Collections;

public class testflip : MonoBehaviour {

	public float myRotationSpeed = 100.0f;

	public bool isRotateX = false;
	public bool isRotateY = false;
	public bool isRotateZ = false;

	private bool positiveRotation = false;

	private int posOrNeg = 1;

	// Use this for initialization
	void Start ()
		//get current rotation
		GetComponent<Collider>().isTrigger = true;
		if(positiveRotation == false)
			posOrNeg = -1;

	// Update is called once per frame
	void Update ()
			//  Toggles X Rotation
			if (isRotateX) {
				transform.Rotate (myRotationSpeed * Time.deltaTime * posOrNeg, 0, 0);//rotates coin on X axis
				//Debug.Log("You are rotating on the X axis");	
			//  Toggles Y Rotation
			if (isRotateY) {
				transform.Rotate (0, myRotationSpeed * Time.deltaTime * posOrNeg, 0);//rotates coin on Y axis
				//Debug.Log("You are rotating on the Y axis");
			//  Toggles Z Rotation
			if (isRotateZ) {
				transform.Rotate (0, 0, myRotationSpeed * Time.deltaTime * posOrNeg);//rotates coin on Z axis
				//Debug.Log("You are rotating on the Z axis");

Obviously you’ll need to customize that script but it shows how to rotate objects in C#

@putin2001 error:
Assets/Standard Assets/Characters/ThirdPersonCharacter/Scripts/ThirdPersonUserFlip1.cs(4,14): error CS0101: The namespace global::' already contains a definition for testflip’