Yeesh... Say, kids! How would you like Centipede, but with mushrooms that moved? Well... oh, sorry, I forgot to say SPOILER ALERT. Guess that's applicable to games as well. Well, there's basically four levels. The first phase involves the excitement of passing between posts. Careful! They move around a lot. You just might end up hitting them! Especially as the game progresses to higher and higher levels. The second phase is much like the first, only with the addition of aforementioned flying mushrooms. They come at you from behind, go off way into the distance, then come back. CAREFUL!!! They change altitude. Don't fly low when they first come at you, and don't fly high when they come back.
The third phase involves posts, mushrooms, and these new bouncy things. A minor irritant, until they start shooting at you. The major irritant: the bullets don't fly at you in a dimensionally correct way. Something like that.
In the final, glorious fourth phase, we finally leave the bonds of the planet's gravity and are flying in space like a damn spaceship should! We still got the mushrooms to contend with, but after shooting enough of those, the big final ship makes its appearance, and what a wondrous sight it is. Kinda like the big final ship in that game I like called Gauntlet... not the Atari Gauntlet, but rather Donald Lebeau's Gauntlet. I think I reviewed it once... let's talk about that one instead! The point ultimately being, the big final ship isn't all that big. Kinda like the world's tallest midget. But, what do you expect? It's an Atari! 16KB-48KB per game, for God's sake! PCs have 2GB of just RAM!