Usually the problems with BitTorrent downloading are that there are no or not enough seeds, or that those who are seeding are uploading very slowly.
But Majora's Mask has more than enough seeds, which suggests that the problem may be your ISP. The "Bad ISP" list Dromiceius mentions is located
here.
Also, if you're using a NAT router or gateway, follow the instructions at
http://www.portforward.com/ and see if that helps at all. With BitTorrent, users who don't upload (for example, because of being behind a NAT router with ports closed) get slower download speeds; but again, the Majora's Mask video should have worked reasonably well despite this. Check the ISP list.
As for codecs, do read the
FAQ. I use the
K-Lite Codec Pack (I do NOT recommend the "Mega" pack because it tends to be out of date) with Windows Media Player without problems, and that's the particular solution I personally would recommend if you use Windows. Just be sure to take the time to read the codec descriptions so that you know what you're doing. Also, be sure to select
ffdshow as your H.264 decoder instead of CoreAVC, or else the videos will come out looking garbled.