C64 Version, Just loved the Whistling shells, followed by the sploooosh sound FX on the Battle Stations section. Also the sweet sound of your anti-Aircraft guns.
Also, the risk factor-Brave the secret passage section or go direct, but face more aircraft?.
I owned and liked Amstrad version, but I remember at the time this was always thought of as 'c64' game in playground spats. And the playground never lies.
I played the C64 version as a kid and it's hard to look past that. But I tried the Atari 8-bit version recently and there's barely any difference, except that the colour is a bit more vivid on the A8 version.
Soon you will have forgotten all things: soon all things will have forgotten you. (Marcus Aurelius, Meditations, Book 7)