Just changed from old BB2D to Max, but some commands are not supported...
loopsound command
loopsound command
There is a loop flag in LoadSound().
mp3 format
Use OGG instead. It offers better compression and no licence restrictions. Alternatively you can buy yourself an FMOD licence and use that.
mpeg movie playback
Well, its hardly a big loss. joypad reading is different?
Its largely the same. If you're having problems then you should maybe start a thread in the BlitzMax Beginners Area or BlitzMax Programming forum to help resolve it.