Can anyone give me a list of rom hacks that work on SNEmulDS. I'm using an R4. I tried The Legend of Zelda: Parallel Worlds and it worked. But then I tried New Super Mario World: Around the World and it didn't work. Please help.
Not really going to happen for multiple reasons.
1) SNEmulDS is a fairly weak emulator of the SNES.
2) SNES ROM hacks have a nasty history of abusing flaws in old emulators to allow them to work where they would not work on hardware
3) In recent years ROM hackers have taken to expanding the scope of SNES ROMs quite extensively and that could well place it into a different category of ROM, or simply require a more accurate/powerful emulator.
In general if the base game works you stand a pretty reasonable chance of having it work with a hack. When the hacks start doing massive changes to things that bother the code then that is a different matter. Many older hacks, particularly of mario, are troubled as there will either be the things to abuse those flaws or be changed so radically that they warrant more emulation ability than SNEmulDS (and all the other DS emulators) provide.
Do make sure to check in a PC emulator -- SNES ROMs variously want headers or don't depending upon the patch chosen (read the NFO or download pages) so you might just have messed up the patching.
The devs of the various SNES emulators (and flash carts as it appears there) don't gate things off and cackle manically to themselves that they have denied their users the option to play something. Such things are physical extra chips that need to be recreated or otherwise handled and if you have limited resources (like you will on the DS -- it is mostly a 66MHz ARM9 with just under 5 megabytes of memory when all is said and done) then you might not even be able to do anything like real time emulation of such things.
Why do they not care about consumers? A lot of people, including me, are yearning to play games like Super Mario RPG, Star Fox, Yoshi's Island, Kirby's Dream Land 3, Mega Man X2, and more SNES games with enhancement chips on this emulator on the DS if they don't have money and only have a DS and a cellphone, like me.