Rotating GameObject to mousePosition

[Kurt-Dekker]

You may be able to simply drive transform.forward (or transform.up when in 2D) equal to your movement vector.

Otherwise, use Mathf.Atan2() to derive heading from cartesian coordinates:

yAxis rotation parent object.

Line 10 is your problem. Subtracting one axis from another does not give an angle. In fact, it is mathematically meaningless. Basic trigonometry tells us that the tangent of an angle is the opposite side over the adjacent. Remember TANOA from algebra in school? The function I suggested is called Mathf.Atan2() for a reason: it takes 2 coordinates and returns you the arctangent, which is the inverse of the tangent. In other words, it maps from two orthogonal axis to an angle. This means that…

Sine/Cosine/Atan2 (sin/cos/atan2) and rotational familiarity and conventions

Vector2 from an angle

This is actually an extremely important and teachable point… games are all over the place on this point, and every engine is a little different. For instance Unity is a left-handed engine (look up what that means on google), and it has conventions about what rotations do and which way is considered “zero.” I try to make most of my games have zero point directly north with angles going clockwise, a throwback to olden day sprite systems, but any mathematics text or scientific text will have zero…