AlienCruise

Story-related; cannot be missed. This unlocks upon completing Star Toltec, the planet in the lower right corner.

The first stage is really easy, and only consists of a bunch of ships that are destroyed in one shot. This transitions right into the second stage, which is just a miniboss fight. The goal is just to shoot off all four people on the top of the ship, so dodge the projectiles and keep focus on them. When the ship leaves the screen, go to the right side of the screen and towards the bottom to dodge either the flames or the bullet hell that ensues, then go right back to position firing on the people to defeat the miniboss.

The third level focuses mainly on obstacles that you'll need to dodge, rather than enemies. As long as you time your movements, this level shouldn't pose any problems. The level ends with a short fight against a face that shoots balls at you. Stay high and you should avoid almost every ball, and the miniboss will go down quick. The fourth level is more obstacles. Use your dash to get through the red and orange jaws that try to crush you. The rest of the level is as straightforward as the previous one.

This boss fight is one of the easiest in the game. You'll fight three mages, one at a time. The first one just uses basic electricity attacks that are easy to avoid. The second has an attack that he'll use after a few seconds to make fireballs rain down, and this is almost guaranteed to catch you off guard and kill you. The only real way to avoid it is to go on the left side of a pillar near the bottom so their angle can't hit you. The third mage has simple ice attacks that are again very easy to dodge, and he should go down quickly. Once all three are dead, that finishes this stage.