it is JUST missions, one after the other with very little in the way of story or any other bs. Armored Core in its purest form perhaps. 100 missions is a LOT though, and quality can vary drastically and it can be very tiring if you're trying to do it all in one go - pace yourself on this one. Got pretty burnt out about 2/3 of the way through, but I do want to go back and wrap it up