I’m currently working on a space shooter (very early stages, but I’ve done quite a lot). I have 2 enemy types so far – a spacecraft which can follow predetermined paths and take random pot-shots at you, and asteroids which come tumbling down the screen at random angles +/- 30 degrees. Although the gameplay is 2D, I’m using 3D models, and the little animations (like banking over or spinning) really adds a nice pop to the visuals. I’ve created a system for importing CSV data from files for the enemy waves. This makes the setting up of enemy patterns really fast and easy once the groundwork is in place.