Scuttle130 said:
If you run a two-scan line type set up, do you have to do anything special to detect sprite colision if you are running 2 sprites on one scan line and 2 on another???

Like Thomas said.
But I have never never never used hardware collision detection for any of my games. The problem is, hardware collision detection is pixel perfect, so if the hair on your character's head touches a leaf of grass.... the guy has to die. Typically, we want to have SIGNIFICANT collision before actually deciding there IS a collision - and so I have always used software techniques (typically bounding boxes, but also sometimes bounding circles). It's fairly simple and not computationally too expensive, if you do it intelligently.
Cheers
A