Ditto on Robocod.
What about Sleepwalker? Lost many a weekend to that.
A few more I can think of : Zool 1&2, Superfrog, Xenon 2, SWOS 96/97, Another World, Flashback etc.
I had possibly the most impressive collection of pirated Amiga games in the world, I once counted over 700 disks. Shame I was too young to really appreciate what I had.
£50 for the Amiga 500 (with expansion board), and all those games, cant believe my dad gave it away when I got my first PC.