I set a collision on the enemy then destroy and the collision was for the bullet but he keeps going/
if the projectile is too small, or moves too quickly it can pass “through” another object without colliding. This phenomenon is called “tunneling” or “ghosting”. You can google “physics engine tunneling” if you want to know more, but the best fix is to slow the projectile down and/or make it larger until this no longer happens.
i ran into the same problem except the bullet kills the enemy but if i or the enemy touches any object we are killed how do i fix that?