just bought this and launched first mission (story). no manual, saw no mention in help/controls menu -- any way to save game in-mission?
There is no in-mission save. There are checkpoints so you can restart from a checkpoint if something happens in the mission that you didn't like. But you can't quit the game and restart at a checkpoint.
The missions are pretty short so it's not "annoying" if for some reason you wanted to quit half way through a mission. You would at most have to replay a few minutes.