1. Mindwalker (IIRC)
2. Probably some variant of Minesweeper
3. Good question, probably an Arcade conversion like Outrun or super hang on. Though I do remember talk of some C=64 game being first... hmmm
4. After the A500 was released almost all ST games were ports from the Amiga...
5. I think it was Shadow of the Beast 2 (came with the A500) -Edit- I know I played Newzeland Story on a friend's A500 before I got an A500 :-)
6. Megalomainia (which was the first game I bought)