I've already looked this up and couldn't really get a straight answer. The trophy description reads "Win all storyline campaign missions (not including What-if missions) playing either Online Versus, or in Hard Mode". I beat all the missions with the same character, with it set to versus and didn't get the trophy. Can someone tell me why I didn't get it? There wasn't always human players on the opposing team, is this the reason? The description seems kind of vague. I don't really want to play solo against the AI on hard if I don't have to (I'd rather play with humans). Thanks for any info.

hopefully you figured it out by now. if not, you wee suppose to play either HARD MODE or ONLINE( notice when you switch to versus the difficulty turns to N/A). that right there is why you didn't get it.

In the posters defence the trophy does state Hard Mode OR Online Versus. The way you're suggesting it seems to be you'd have to play Online Coop because you could set it to Hard. Otherwise you've simply restated what the poster already knew as they stated they played Online Versus already. -.-;