Unity Symmetry and Animation Curves
You can use simple symmetry and animation curves to get make cool enemies in a space invaders clone. I use Animation Curves that cycle through different body part rotations for enemy animations. The benefits of Animation Curves are that you can draw neat shapes that act as easing effects without having to use algorithms to calculate the easing effects. You can combine all sorts of bouncing, easing, and shaking effects for both rotations and movement.