Now, we don’t normally post a lot about fan-made games around here, but this case deserves a bit of special attention. The premise here is plain and simple, turn Nintendo’s money-printing Pokemon franchise into a 2D fighting game. While this might have been done before in countless Mugen mash-ups, this one looks like it was built with a decent amount of effort. It shows, since the quality of the animation, though a little janky at times, does look quite good. The actual fighting looks fun for a doujin game; it utilizes assist characters, and has some semblance of a combo system. You can get the game through here and even view a tutorial for it here.
For that other Pokemon fighting game: read Pokken Tournament