The first thing you have to recall to get this movie is that, in Cataclysm, the level cap is going to be raised to 85. I know, it's a subtle thing, but that's the fact that 84 85 - World Of Warcraft (Cataclysm) is based around.
This video by the Unforgiving is an interesting parody of 74 75 by the Connells. And while the Connells are waxing nostalgic in their original song, the Unforgiving is looking forward to 85 in Cataclysm. The video has a lot of extra bits throughout its runtime, focusing on the various misadventures of a Tauren. I'm not always sure how it directly relates to the song's content, but it's pretty amusing.
Ultimately, I really liked 84 85. However, I think it had a little bit of schizophrenia between the cut scenes, the video, and the song content. It made it a little hard for me to figure out what's going on, and I think ended up detracting from the overall effect. The song, the music, and the video itself were all entertaining and fun. However, when it blended together, it lost a little bit of the total effect.
I'd really suggest taking some time and dropping the Unforgiving some positive feedback. I'm really hopeful about any future musical projects, and would like to see the video get the praise it deserves.