Eerr. You english people with your odd expressions... Tell you apart from Windmill? If you're stuck I'd rather use an axe than telling stuff. Umpf...a bad one.
However, in case you mean why I like it....
First of all Windmill is even slightly gayer than George Michael's "Outside". I always skip it nowadays

But Chameleon is my first CD ever, I got it 1993 or 1994 as christmas present. After listening to Keepers it felt really odd as you may imagine. However it's been growing in me since and after a few years I started to like it, and nowadays I think it's a masterpiece and the funniest thing is that it still keeps growing, after ten years! I honestly think it's Helloween's best album, and an important part of my musical growth. And Kiske is still the one vocalist I most look up to.
I feel that as a work of art it's comparable to Mr Bungle's California, which is another crossover masterpiece. Chameleon of course isn't nearly as wacky and clever in putting styles together, but there we have to remember that Helloween are powermetal, not a bunch of jazz guys straight from institution
Thanks for asking, I regularly feel the urge to praise the album anyway