I beat it on Beginner thanks to a liberal use of save states. I didn't like it enough to seriously try beating it on Expert. This is one of the 6 hidden games on the Mini.
I guess this is a sequel to Gradius. The 6 stages alternate between being horizontal and vertical. After you defeat the end boss and the credits roll, it loops back to the first stage with it becoming harder. While you keep your score, you lose all power ups. I believe it loops many times. As with a lot of shooters, the power ups and weapons are released by shooting down specific enemies. There are only 3 different weapons, with each being able to power up, I think, once. There are also speed boosts and a shield that attaches to the front of your ship that can absorb about a half dozen shots or destroy some enemies by touching them. What I think is the main feature that makes this somewhat different is that some enemies drop a companion ship, in the form of an elliptical glowing ball, which can shoot the same non-missile weapon that you currently have equipped. You can get up to 5 of these extra ships. By moving around the screen, you can cover a good chunk of the screen between the 6 total ships. Thankfully, the other ships are not affected by the terrain and fly through it.
There are several places where there is some serious slowdown, which having the full compliment of extra ships, as well as the missile weapon, will help to cause. Based on when several of these occurrences are, this might have been purposely done. The bosses are all pretty easy, as long as you have a full compliment of upgrades. The stages mostly come down to memorization of their layouts, which is pretty standard from my experience. There's no tactics to when to fire, so you could simply put both turbo switches up to max, tape down both buttons, and just worry about navigating your ship around the screen. While it shows a High Score, it never gives you an opportunity to enter your name/initials when you beat it, and it doesn't have a High Score list. It also doesn't replace the default High Score when you do beat it.
