Deep! To say the least...
The single player has to be played through to unlock the parts you will use to upgrade better mechs in multiplayer. And achieving s on all levels is how you unlock all the parts. However, doing this can get quite challenging.
The multiplayer, with the squads, and the war between the 3 factions, is very addictive, and will cause you to be filled with reason to go through the story getting s ranks. Trying to get better parts to build better mechs...
Over all, chromehounds is a buy if you have xbox live, if you don't, then I don't really see how this game could be that fun...