What is the theological difference between Catholicism and other Christian denominations?

Contrary to fundie beliefs, Catholicism is not set apart as any "different" form of Christian religion. The beliefs among Christian denominations varies greatly from one to another and, when comparing all Christian religions, not just fundie ones with Catholicism, Catholicism really doesn't stand out in the crowd has having something about it which is fundamentally "different". It's just the focus of a lot of fundie hatred because it was the first church. They have to defend their relatively new religion as being the "one true" religion by attacking the one they branched off from.