This is a basic mouse input class to be customized for a particular game’s needs and loaded depending on device. Note that unlike the Keyboard_Input class, this requires tweaking the Input Manager in the project settings since the default are not fully compatible with this (in my opinion) more optimized script.

Mouse_Input.cs

using UnityEngine;
using System.Collections;

public class Mouse_Input : BaseInputController {
    private Vector2 prevMousePos;
    private Vector2 mouseDelta;
    
    private float speedX = 0.05f;
    private float speedY = 0.1f;
    
    public void Start () {
        prevMousePos= Input.mousePosition;
    }
    
    public override void CheckInput () {
        // get input data from vertical and horizontal axis and store them internally in vert and horz so we don't
        // have to access them every time we need to relay input data out
        
        // calculate a percentage amount to use per pixel
        float scalerX = 100f / Screen.width;
        float scalerY = 100f / Screen.height;
        
        // calculate and use deltas
        float mouseDeltaY =  Input.mousePosition.y - prevMousePos.y;
        float mouseDeltaX =  Input.mousePosition.x - prevMousePos.x;
        
        // scale based on screen size
        vert += ( mouseDeltaY * speedY ) * scalerY;
        horz += ( mouseDeltaX * speedX ) * scalerX;
        
        // store this mouse position for the next time we're here
        prevMousePos= Input.mousePosition;
        
        // set up some boolean values for up, down, left and right
        Up    = ( vert>0 );
        Down    = ( vert<0 );
        Left    = ( horz<0 );
        Right    = ( horz>0 );    
        
        // get fire / action buttons
        Fire1= Input.GetButton( "Fire1" );
    }
    
    public void LateUpdate() {
        // check inputs each LateUpdate() ready for the next tick
        CheckInput();
    }
}

Next Up: MusicManager.cs

Many games have background music. The Music Manager is a singleton in charge of making sure music loads and is played when needed.