It's a good thing developers never tire of coming up with good stuff. LiraNuna, developer of the game Tales of Dagur, has posted the progress of the latest development of his WonderSwan emulator called the dualSwan.

The WonderSwan is a Japanese handheld game console released in 1999 by Bandai. With the dualSwan, you'll be able to play WonderSwan games in your Nintendo DS. How cool is that?

Here are some screenshots to show the progress of this emulator. You can see that the FPS on the screenshots are close to that of the original results on the HW. Dualis refuses to emulate full speed so another ~6FPS had to be added to get the original results on the real HW.

According to the developer, low FPS on games occur because of the poor core implementation of NEC CPU. But he says not to worry as this will be fixed soon.