Receive 300,000,000 points in Score Attack Mode.
Start Score Attack / Extreme / Mission 11
Use your laser the whole time. Drop down shooting some floating laser bots on the way. At the bottom take out the two VS with your laser so if you are lucky you can get 2-3 combo from each one. Don't forget the target marker at the bottom in the middle. On your way up, take out the VS on the ledge, shooting into the tunnel can net you 2 more combo from the box and another target marker if you can nail it from the distance. Continue to head up and finish off the laser bots. Try not to miss any and ascend as you are taking them out. Kill them systematically so you know when you are on the last ones. Head up to the next ring right after you destroy the last one.
As you come up to the ring dont let go of laser so you can hit the next enemy as soon as possible. Take out everybody here with your lasers and again, be sure to keep track of how many enemies are left. As you kill the last ones, you need to be on your way up. To continue your combo outside BE SURE TO SHOOT THE TARGET MARKER that is below the next ring on a ledge in the center. You may have to scout this out beforehand. If you make it to the hatch you will have a fresh combo when you start the boss fight. This way you dont have to bother with slashing him or any target markers outside.
As soon as the fight starts take out the first ring of the tower. All of the yellow dots and smaller red ones that spin around. I found it easier to take out the big ones on each ring after the little ones but this is just preference. After you clear one move up to the next.
The key is continuing your combo outside with the target marker on the way up. This level being so short and close quarters it makes it somewhat easy to practice on and scout out your route.