Question

An AI assistant wrote this Unity (C#) movement controller for a 2D platformer. It runs fine on your 144Hz dev machine but testers on 60Hz monitors report the character jumps less than half as high and feels 'floaty.' Review the code, identify why the physics is frame-rate dependent, and say how you'd catch this before it shipped.

1void Update() {2    velocity.y += gravity * Time.deltaTime;3    if (Input.GetButtonDown("Jump") && grounded)4        velocity.y = jumpForce;5    // integrate position6    transform.position += velocity * Time.deltaTime;7    // air drag applied per frame8    velocity.x *= 0.98f;9    CheckCollisions();10}