No need to present the original Double Dragon trilogy, but I'll talk about the games briefly: the first one is a classic, the second one is a decent sequel (but more famous for its ports), and the third one is a weird kusoge where you fight Cleopatra.

More importantly, what about the port? Well, it's shit.
For the good points, they fixed the infamous slowdowns. There's also an arranged soundtrack for the two first games (pretty forgettable though), and you can choose the "story" mode, which is basically a level select. And that's it.
Bad points are basically everything else "thanks" to Dotemu's atrocious emulation wrapper. Ugly interface, buggy achievements, and strange performance issues (don't know how I managed to beat this with the random stutters).

At least it was cheap.