There are three, fairly simple types, each moving at a different speed as they appear on-screen. Balkiry are the red, eagle-like fighter jets that fly across the screen from the right, at varying speeds. They're easy to kill and cause little bother, and if you miss them, they won't come back to annoy you. Nebula are weird little helicopter badniks that drop spiked balls from their bottoms. They come along in clusters of up to six or seven, in various formations, and hover slowly across the screen, moving up and down occasionally. They can be dangerous when you're taking on a vertically aligned grouping of them, so it's always best to start by smacking into the top one, because of the spiked balls they drop. Finally, Turtloids are little turtle robots that ride on the backs of much larger tortoises. These fly very slowly across the screen, again in groups, and they don't move down or up but the daddy of the twosome does shoot out an occasional tiny projectile from its mouth. You won't be able to hurt him, but you can take out the little guy on top, who controls the big sleepy-looking beast. With him gone, the tortoise (who never actually hurts you when you touch him anyway) remains to act as a completely harmless platform for you, until it departs to the left of the screen.

- This is the first time we actually see Sonic and Tails' plane in the entire series, and it's become a common staple ever since. Though Tails is usually seen as the pilot, the original Tornado is in fact the property of Sonic. Nowadays, they seem to fly various enhanced versions (or the same plane with new enhancements, it's sometimes difficult to tell), starting with the Tornado 2, which is purple, and transformable into a more maneuverable craft.