You can find it in Steam for free. It has Steam Achievements. One of the achievements is Defective Parrot or something like that, and happens if you release your parrot and it's killed in one second. An audio clip plays from the famous Monty Python skit, saying "Right, I'd like to register a complaint!"
This game is awesome.
EDIT: Also, it's a Source mod, as Ebola1717 helpfully pointed out.

You should probably mention that it's a Source mod in your post. it's somewhat misleading otherwise.

Yo, SaunaChum! Where you at?!

Haven't been able to dig my teeth into this game yet, but from the few minutes I've played, it's hilariously fun.

Looks trippy and very tongue in cheek. Will definitely try it out.

Ok, I'm here now Joe. I'll throw a serious recommendation to this game.
I've been playing this mod since 1.0 (played PVK 1 also) and I have then also joined the beta tester team. Finally now we're getting some real balance in the game so now it's the time for everyone to try it. The melee fight and arc-based ranged may at first seem hard but after a while it's extremely fun.

Okay, so I'm going to install HL2 and then this. How big is this mod?

It's good, but the fact that it takes me a LOT of damage to kill knights seems a bit dodge....

i really have to get around to re-installing half life so i can try out all the awesome mods... been on my list for ages..

Seeing as I haven't actually finished HL2 (shhh) I might as well.