I guess everybody bought and played this game when it was new. The game requires you to play through a set of co-op missions to unlock all the titans. After you unlock them there's no reason to ever play them again. On Gaf people picking this game up now can't find enough players playing these missions to beat them all. This locks them out of some of the titans.
Last edited:




You just play through the campaign to unlock them.
That's what i would have done.