Bomb Da Base: Act II" was the peak of GTA 3 for me. The build-up, the sniper action, and 8-Ball's cool attitude made it feel like a real heist. Took me a few tries, but I loved every second of it
Personally, I found in GTA 3, "Last Requests" the most unforgettable. It was not only the action that got me interested, but also the emotional turn.