DS can only emulate the VERY early Arcade/Mame games.
Try 1939 for the NES. It's pretty good. (In my opinion)
~Nero
Did u mean 1942 or 1943? seems that 1939 doesnt exist for NES (atleast i couldnt find it)
On MAME get 19XX: The War Against Destiny. It's not like the earlier 194X titles, this one is fast paced, full of bullet hell and has huge bosses and stuff. It's awesome.
do u have any idea how much megabyte that is? since i'm on 2kbps dial up its so important.