Here's a save with the SDF Main Gun special that I use for NG+ Runs.

The SDF can be dropped in Ice Exit and Ice Secret which is a little out of the way for a traditional NG+ Speedrun, so feel free to use this instead. The save also has some practice saves for the later levels and challenging bosses.

Full loadout is as follows:

Special: SDF Main Cannon Front: Laser Back: Sonic Wave SideKicks: Plasma Storm