GAH! Finally! 

I bought this game ages ago, and I finally got the last stupid achievement today.

You have to beat the entire game without losing a round. Unlike HDR, you can't set the game to one round, so you have to beat all of the world warriors 2 rounds each. Ken/Ryu are nightmares when the computer controls them.

It probably took me 75 tries over the course of year and a half.

I used M. Bison. 

I have 200/200 in SSF2THDR too, so now I'm all set to get 1000/1000 in SFIV! 

Gah!