R4s multiplayer compatibility is average. Some games work, some don't. As for NSMB, I do not know.
DS-Xtreme is best, for both Wi-Fi and Download(system link) play.
I searched for you real quick and found this, from a review about the R4 @ another forum (membership needed to read it)
New Super Mario Bros.This post has been edited by throwingks: Mar 12 2007, 05:16 PM
- PROBLEMS: Plays and saves fine. Mini games section works fine. Download play doesn't work.