- As a fortress planet, you must fly through a ship that in many ways resembles the interior of the Core ships that you invaded in order to obtain new power-ups. The walls of the ship create a maze that you must navigate through in order to survive and reach the end. The edges are lined with cannons, and various enemies fly through the interior, capable of flying through the walls without harm. If you are very high powered, you will be dodging a lot of bullets.
- After flying through a good portion of the beginning of the fortress, you will come upon a much larger craft that only flies vertically, up and down where it is positioned. It shoots a spray of projectiles straight forward, and these projectiles can be destroyed with your weapons. You have two choices; you can concentrate your firepower on it until it is destroyed, or you can simply fly under it when the opportunity arises.
- Beyond the first of these crafts, you will find a hatch along the ceiling that release squadrons of enemies. Try to take it out as quickly as possible so that they don't add to the chaos already present in the fortress' corridors.
- Just past this hatch, you come to a section of the fortress that is covered in a barrier that can be destroyed with your shots. This is no small section of particles like you've encountered in the past, this is a full blown stretch from floor to ceiling, extending quite a long time through the middle of the ship. During this time, you will encounter enemies less frequently, but you need to focus on carving a safe path through the barrier in order to survive. If you're fortunate enough to have two Options, Lasers and Up Lasers at this point, making it through this section will be considerably easier.
- Shortly after this section starts, you will find a time-limited power up, the Option Barrier. Collect it to send your Options flying around the Metalion in a circle, giving you access to shoot out parts of the barrier that you otherwise could not reach. After the first Option Barrier wears off, you can find a second one waiting above you along a wall.
- As you get further along in the barrier, enemies will start to make the journey a little tougher. Two rad cannons will occupy the bottom wall, but a barrier above them can shield you from most of their attacks until you can dart forward to the section ahead of them. Around this time, squadrons of enemies will fly toward you from both the left and the right directions.
- Once you make it out of the barrier, you will encounter another one of the large projectile shooting ships. Use the same strategy against this one. Just beyond it, you will also find the Enemy Slow time limited power-up. Collect it to give yourself a slight advantage against all of the enemies that will appear near the end of the fortress. Just as it wears out, a third large craft will be waiting for you.
- Beyond the third craft, you will be assaulted by a large number of red enemies, which at once puts you in some danger, but also creates a great opportunity to power up the Metalion if you are in need of any extra weapons. This leads to a very narrow shaft that you must fly through. While doing so, an enemy will appear on the left side of the screen and approach you from behind. It will also shoot a bullet at you. If you have Options, fly to the left side of the screen, and then advance to the right a little bit so that your Option remains on the left edge. This way, your Option can destroy the enemy before it has a chance to fire. Otherwise, you will be forced to fly up into the small gap in the ceiling to avoid getting attacked.
- After this narrow section, you will be put through another gauntlet of red enemies, giving you another opportunity to power up. A second barrier phase follows this section, and you must shoot ahead to carve out a path for the Metalion to take in order to survive. Once you reach the other side, you will see a set of blocks on the floor and the ceiling that begin to move and bounce back and forth while you progress to the right. The scrolling will soon stop when you reach a ship.
- When the scrolling stops, you are forced to destroy the ship on the right that moves up and down. All the while, the bricks that started moving when you arrived will continue to float up and down, creating a dangerous area for the Metalion to occupy while trying to destroy an enemy. The best strategy against this enemy is to fly as far to the right as you can until you are forced to double back away from the enemy. Hopefully, you will be able to leave an Option or two in the close vicinity of the ship so that you can fire frequently and pummel the ship with your Options before you are forced to back away even further because of the moving blocks. Once it's destroyed, you will proceed to the boss.
Boss: Abaddon Ship
The Abaddon Ship is the most aggressive ship that you will face in the game. The core and its shields are protected by a giant array of lasers that fire directly in front of the center, making it next to impossible to get a direct shot off with the Metalion itself. Having Options in this battle improves your chances substantially, since they can sit in the line of fire and still be able to shoot at the shields and the core. Provided you have Options, your goal will be to keep the Metalion out of the line of fire, but only just barely so that your Options can lag behind you and be able to fire at the shields. Ideally, you want to wait for the Abaddon to start firing it's laser while it's moving toward you. Then while the laser is reaching the left side of the screen, fly in the opposite direction as the Abaddon to avoid the laser, and lure the ship in that direction on the next shot. You will volley back and forth until you manage to chip away at the shields and shoot down the core. Just be cautious with your timing, and don't accidentally try to cross over while the laser is still being fired.
Note that after you beat the Abaddon, you will receive a distress signal, and discover that the fortress was a trap to lure you all the way out into far space, while the real threat was closer to home. As a result, you must now travel back through all of the previous six stages in reverse order before you can face the real threat and save the solar system.
Nemesis '90 Kai changes
For the most part, the remake of this stage remains true to the original. However, due to the speed of the game, and the amount of damage it takes to remove certain obstacles, it presents its own set of challenges. The craft that fly up and down, as well as the mid-boss which appears when the scrolling stops, seem much easier to defeat. If you are fully powered, they won't be able to withstand your attacks for more than a few seconds. However, the full screen barrier that populates two sections of the stage is a bit harder to deal with. Even at full power with four Options and Lasers activated, you may have a hard time punching a wide hole through the barrier. The Lasers don't feel as effective in this section, and you'll want to minimize the amount of movement you make vertically through these sections. Grabbing the time limited Option Barrier power-up will certainly help, but not quite as much as you'd think. As stated above, the mid-boss that appears near the very end of the stage when the scrolling stops takes less damage to defeat, but it is still tricky to line up a shot at it with all of the blocks rising and falling. In addition, there is yet another set of rising and falling blocks that has been added beyond the mid-boss that you must navigate through in order to reach the Adabbon.
Despite how dangerous this ship is, it feels slightly easier to defeat in the remake. It doesn't pursue you as relentlessly as in the original, giving you more opportunity to avoid getting caught within its giant laser, and to line up your shots at the core and its shields with an Option or two. You can't access the core of this ship once it's been defeated; the game will kick you right into the next part of the story where you are recalled back to planet Gradius in order to defeat Venom's ship before it's too late. At this point you will begin to fly through repeat instances of the stages you visited in reverse order. However, in the remake, these stages are often condensed versions of the first pass through them. Though shorter, they are no less difficult to clear.