Controls for a camera with 5 degrees of freedom in Unity3D

Unity3DCameraMovement.cs

using UnityEngine;

/** 
 * Controls for a free-roaming camera with 5 degrees of freedom (rotation around z is disabled)
 * Uses default input axes with the scroll wheel for moving up and down - Shift/Control is also a nice idea
 */
public class CameraMovement : MonoBehaviour
{
    /** absolute rotations kept separately from the attached GameObject */
    private float rotationX = 0f;
    private float rotationY = 0f;

    /** multiplier for camera rotations */
    public float cameraSensitivity = 5f;
    /** multiplier for strafing and moving forward/backwards */
    public float movementSpeedXZ = 1f;
    /** separate multiplier for moving vertically since the scroll wheel can be awfully slow */
    public float movementSpeedY = 5f;

    /** rotates and translates the GameObject */
    void Update() {
        var newRotationX = (rotationX - Input.GetAxis("Mouse Y") * cameraSensitivity) % 360;

        // keeping the angle around the x-axis between -90 and 90 degrees
        rotationX = Mathf.Max(Mathf.Min(newRotationX, 90f), -90f);
        rotationY = (rotationY + Input.GetAxis("Mouse X") * cameraSensitivity) % 360;
        // setting rotation directly to avoid tilting around the z-axis
        transform.rotation = Quaternion.Euler(rotationX, rotationY, 0);

        transform.Translate(
            Input.GetAxis("Vertical") * movementSpeedXZ * (transform.worldToLocalMatrix * transform.forward)
            + Input.GetAxis("Horizontal") * movementSpeedXZ * (transform.worldToLocalMatrix * transform.right)
            + Input.GetAxis("Mouse ScrollWheel") * movementSpeedY * (transform.worldToLocalMatrix * transform.up)
        );
    }
}