So out of boredom, I decided to watch the Hellsing anime... (spoilers)
What. Have. They. Done. !?.
They destroyed it.
Let's start with the art. Integra actually looked female (and smoking small cigars?). Seras looked like young Alphonse Elric. Anderson didn't looked the same. Walter...what the hell did they do to Walter?
Now don't even get me started on what they did to the characters. Seras was an innocent weakling. Anderson wasn't nearly as badass as before. Even Walter got a downgrade on the badass-ery.
I didn't really have any qualms about them turning Integra into a PMS-y bitch throughout the first few episodes, but what the hell did they do to Alucard? I swear, if manga/OVA Alucard could see what they did to his character, he would CRY.
They made him...almost nice.
They completely destroyed the Alucard/Integra dynamic.
Manga Alucard: You may be my master, but I can still piss you off for the sake of my own amusement!
vs.
Anima Alucard: Yeah, Integra, I sort of respect you.
What the hell?
Another example (after first fight scene with Anderson):
Manga Integra: My vampire is awesome and can kick your ass!
vs.
Anime Integra: Bad boy! You almost got defeated! I won't tolerate your failure! (while Alucard says nothing (?))
And don't even get me started on the part where Alucard gets all preachy (WTF?) and goes on about how Integra "will never give up!" (That was the episode where I REALLy wanted to tear my hair out.)
The ending involved Alucard fighting some other uber-powerful vampire. Why did they have to add this uber-powerful vampire? Because they failed to make Anderson cool enough.
Anyway, here's a brief synopsis on the series:
Episodes 1-3: Correspond to the first manga volume.
Episode 4: Pointless filler.
Episodes 5-6: Basically the same thing as the second manga volume.
Episode 7: Highly disappointing fight scene with Anderson.
Episodes 8 & 9: Vampire psychedelics (?) And a lot of new characters.
Episode 10: Horribly cheesy episode that made me scream and pull at my hair.
Episodes 11 & 13: Final battle. And vague ending.
I actually have no problem with the vague ending. The last thirty seconds of the show was the only part I actually liked.
That, and there was no annoying major.