I remember that one. It still missed quite a lot though.
For example, there is an entire final boss simply NOT present in the Dreamcast version. Instead, they simply gave the games (recurring) sub boss more HP at the end, making him harder/longer to defeat. There's also some of his animation sequences missing in the DC version. For example, in the NeoGeo version, at one point, he flies ahead of you, firing from the rearside until you take him down a little, then he animates as he swings around and turns to face you to continue a different attack pattern. On the DC, he appears facing you and leaves facing you.
There's additional level detail missing from the final stage too (in Normal Mode) that overlays the bottom scrolling layer. However, they also omitted in the Neo's Manic & Omake modes too, so it obviously hindered performance when there is more action on screen.
There's more, but I think I've said enough