I see a few people mentioned Fairy Tale adventure. I quite liked this back when it was released. Me and my brother were playing it at roughly the same time. Being that he was more single minded with his games than I was (I'm more inclined to play a few games off and on at the same time) he progressed more quickly than me and got maybe 3/4 of the way through it before I accidently overwrote his save games with my own.... he wasnt happy with me :-) There is a PC version that was released at a similar time, but was also a sequel made for PC only. It's amazing how few amiga specific games there are, even if some started life on the amiga.... 90% or more of the games people have mentioned here also had pc versions, some even updates/remakes and/or sequels.
Back on topic, most of what Id like has been mentioned already, but I'd really like a revamped Z-Out (well, any of the better Amiga 2d scrolling shooters, but that was one of my favs.).