This has to be one of my favourite games at the moment. i originally bought it because i was a fan of the series when it first was released on the playstation.
having recently bought a 360 i thought i would buy this to catch up with the series.
there are around 40 single player missions to get your teeth into as well as single player one vs one against the enemy acs. these are pretty varied from one to another going from tackling other acs and destroying compounds to battling oversized arms forts which dwarf your ac by a ridiculous proportion. these all add up to getting new parts to use on your own ac. this allows you to customize your own with a wide variety of parts to suit any fighting style.
as for the multiplayer online, if you dont find the single player much of a challenge i assure you some of the opponents you will face online will definitely give you a run for your money.
definitely worth a 5 out of 5.