AlienCruise

Story-related; cannot be missed.

The Land of Neptune is the blue planet in the upper left corner. The first stage is pretty simple. The main new obstacle is the tentacles that come shooting from the top or bottom of the screen. Keep alert to the bubbles that indicate where they're about to come from. The second stage is much more dangerous. In addition to the tentacles, there are currents pushing you up or down, and there are dark blue reefs on the top and bottom. These look innocent enough, but get too close and tentacles pop out and instantly kill you. Between dodging them, the normal tentacles, and all the enemies, this is one of the tougher stages. The midboss at the end of this stage is surprisingly easy though. He's first just a head/egg without any real attacks. Unload on him to break the egg open. Now he will shoot some projectiles at you, but many of them can be shot and destroyed. Focus fire on him and he'll be defeated very quickly.

For the third stage, you have two options. Shortly after the stage starts, you'll find a red gun powerup near the ground that shoots rotating directions. If you grab this powerup, the rest of the third stage will be very easy. However, this gun is absolutely horrible for the boss right after this level, making the fight much longer and more difficult than it otherwise would be. The second option is if you still have the shotgun powerup from the second stage, you could skip the powerup in the third stage. This will make the bubble sections much more difficult to get through in the third stage, but the shotgun makes the boss incredibly easy, since you can destroy all of his projectiles with it and keep hitting him.

The boss is a squid whose eyes need to be shot quite a lot. He shoots out different types of projectiles, but they can all be destroyed with enough bullets. If you can't destroy them, you'll have to dodge them. Stay on the far left of the screen and you should be able to dodge them without much issue. Tentacles will fly in too, but pay attention to the bubbles and you shouldn't have any problems avoiding them.