Oh dear. Where to begin.
I bought this game when it was first released, despite having read some really -really- terrible reviews. 'The interface is clunky' they said. 'The landscapes are vast, hideous and barren,' they said. 'And it's not funny, either.' How could I believe any of that, having played the first two games?
Well, to cut it short, they weren't kidding. The developers had originally planned to stick to classic 2d, but changed tack mid-way : the game was in development hell until a few years after the success of Lucasarts' fantastic Grim Fandango, which boldy plunged the point-n-click adventure into half-3d whilst arguably heralding the beginning of the end for the 2d interface. You can see their reasoning for the change, but it's a terrible shame they didn't hold firm because Simon 3D is, without a doubt, the worst 3D adventure game I've ever played.
I may have played it through to the end, I can't remember - I seem to be repressing the memory. If it's a choice between buying this for a fiver or downloading Beneath A Steel Sky for free, for the love of God don't buy this.