He's got an acid etched sword, his glaive is silver, and so are the stakes. And he's got his serum and I think silver bullets or explosive rounds or something.
But the twipires have none of the traditional weaknesses of vampires, are bulletproof, hard as diamond, etc, etc... They're mid-tier superheroes with the title of vampire.
Stephanie Meyer took Interview with a Vampire/Dresden Files(The Vampire Courts) and basically ran with it. She took all the badass parts, ramped them up to 11, then cut out anything that could count as an actual weakness aside from "supernatural creatures can kill supernatural creatures". You're right that it's awful as a vampire franchise as it disrespects what we all typically associate with the term. But the action scenes are cool. Actually I'll give another credit that the individual vampire powers can be pretty creative and interesting. Like Bella's being a mental shield that basically protects anyone she wants in a close enough radius from any sort of mental power. But aside from that...