Introduction to Physics in Unity
Objective: Enable a gameObject to use Physics while in Unity, for events such as gravity, or collision.
The example shown here is on our Enemy prefab, because the Enemy will collide with the lasers and the player, it made sense to put the rigid body on our enemies. any Object that needs to collide at some point needs to have a collider, and you only need a rigid body on one of the objects in a collision.
taking for example our player, which has no rigid body, because the enemy will collide with the player, and already has the rigid body. if we wanted to we could have the units obey the laws of gravity in the rigid body settings. However, we essentially create an artificial gravity, in our static movement speeds down the screen, so gravity is not needed for this game.
Therefore we turn off gravity, and let our code move the enemies/laser shots, and our player is of course controlled by movement keys, WSAD and the arrow keys.