The C64 version of Turrican 1 is really a masterpiece and of course the game is still great on the Amiga, but for me it's too close to the C64 look. Turrican 2 looks quite different on the Amiga and in my opinion at least way better (even better than the 'improved' PC version). Guess that's the main point why reviewers gave it better ratings than Turrican 1, because the second part fully looks like an Amiga game
Edit: While we're at it... I'll never get why the speech on the C64 version is longer than on the Amiga.