Blue Max 2001 (1984)

In this sequel to Synapse's Blue Max, it is the year 2001 and you are flying a flying saucer. You're trying to bomb enemy targets while not getting shot (or rammed) by enemy saucers or shot by ground cannon. If the screen border starts flashing yellow, you are dangerously close to the ground. If the border is red, you are hitting the ground. If the border is gray, you are flying low but not TOO low. If the border is light blue, then the enemy ship is a the same altitude as you.