Snake looks like some anime samurai dude or whatever. Good art, but doesn't seem fitting for Metal Gear. I guess anything non Shinkawa doesn't feel right at all.
The art was done by Masao, he did ZOE2's character art previously. It makes sense that Shinkawa isn't doing these considering its not part of the main series. Shinkawa didn't do the character art for the GBC MG either.
The art in the game is pretty much of the same quality :\. Sometimes it looks cool and sometimes it looks blah.
The game is uh... not exciting. But it's interesting. You have to be in the right kind of mood to have fun with it but I'll admit I'm not in a MGA mood a lot. It's my most neglected PSP game.