Spy Hunter was the first game I thought about however I think it was too advanced for my first Amiga project so i went a little easier :)
I think Spy Hunter can be done, but i think it might need AGA as it has more colors on screen
Maybe reduce the colors a bit. I am no expert but should not be very noticeable I think. Cool you though about it. Really a classic! Your programming skills seams great and no problem with AGA but OCS is where the real challenge is ;)