This has been posted by others before, but I thought I'd throw it out there again for those having trouble. I got the game running, but it would frequently crash during cut scenes, and I had other issues, where "loading" would stay on the screen and doors wouldn't open. At the time, I was using ciosxrev20b/57/249; I tried using ios56 as well, with no luck. I was about ready to give up - I have a copy on pre-order with Amazon anyway (and I hope all of you playing this have also pre-ordered it or are planning to buy it!). Then I tried one more thing - shifting to ios222/223 - and I've been playing for hours now without issue.
Here are links to the steps I took to get this working properly (from a USB HDD):
1) Download
http://cfg-loader.googlecode.com/files/cfg59a-222.dol, put it in a folder called "cfg loader" or something appropriate, inside the "apps" folder of your SD card. Don't forget to rename cfg59a-222.dol to "boot.dol"
2) Next, follow all the steps on this page:
http://gwht.wikidot.com/ios236 - download and run IOS236 installer v1. When you're installing ios236, select "I have no use for pirated games," otherwise you'll go through some hassle as the coder chides you for piracy; you'll have to delete the installer from your SD card and re-install it. Again, select "I have no use for pirated games," I think it's option 2.
3) Follow all the steps here next:
http://gwht.wikidot.com/hermes-ios222-223 - it's very important you go through ALL steps 1-12 in the installation procedure section.
4) Launch the homebrew channel, run cfg loader 59a 222, and select your game from your appropriate storage device. If it tells you something about FAT partitions and no partitions found, select the WBFS partition I'm assuming you've already set up on your HDD. No further configuration is necessary.
5) Enjoy the game, and if you like it, buy it:
http://www.amazon.com/Metroid-Other-M-Nint...7890&sr=8-1