Not my favorite band by a stretch, but Gamma Ray is 100% power metal, and nothing in it reminds me remotely of Pet Shop Boys... If anything, it's the unshakeable Helloween influence that brings the melodic happy metal vibes.

Yes and no. The first records are a genius mix blending power metal and synth like rhythms.

I think there's a noticeable difference from the block of 'Heading for Tomorrow' until 'Insanity...' and 'The Land of the Free'.

Then there's a pure power metal band.

That's just the Kai Hansen doing his thing. He's also been quite active as a producer.

I don't know if there are any bands that stay in a single narrow style forever. And I don't know if Gamma Ray could fit just one style too - there is Power, Glam, Speed Metal in their songs.

Just a personal bit -- Gamma Ray's "Real World" "got me", or "clicked" at some (rather dark) point of my life, and made me look on life's complicated absurdities from a bit different - lighter - angle. If anything, I am grateful for that.