This is a video which shows the differences between the different versions.
[youtube]C3b4h-MUjGo[/youtube]
There is another which shows the different versions of SOTB2 which is even weirder. I'll try and find it. Also there is a podcast which goes through every version with the music and sound effects. It has commentary and everything.
I honestly never realised how good the Amiga version was... I just accepted it as normal.
I always preferred SOTB 2 for both game play and graphics/sound. The only thing it lacked was checkpoints.