It’s just sad that there isn’t much anime flash games to play online. I did find some cool games, though. One of the best is SD Gundam Capsule Fighter, it’s a single-level shooting advergame to promote an MMO of the same title.
Anime dressing-up games are the most common. Most of the characters, however, are generic ones. There are some Naruto, One Piece and Dragonball games.
This lack of free anime-inspired games is most likely caused by copyright infringement fears. From what I know, flash game developers submit their creations to distribution websites like MochiMedia for monetization. Any game with copyrighted content will not be approved. So there’s no money in making games featuring our favorite anime characters.
So if you’re looking for anime flash games, it’s best to not let your hopes up. There aren’t that much to play…and most of them are dressing up games. :)