I have it. To play online, go to Match (The X next to Training on the menu). You can then play either original infrastructure or the + version, although special characters (Old Snake/Raiden) cannot be used in the original version.
It's not a bad game, but it's what it was advertised to be - an expansion to Portable Ops. In that respect it does feel shallow, since there are NO story parts in the entire game, it's all missions.
Constantine
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