You get one for buying the collectors edition, called "devoted fan". Others you get for trying out of the ordinary things. For example, the mission where you harvest the special gas on a Protoss planet. The objective was to get a certain amount of gas, not to kill the enemy entirely. However, I did try this. The result was getting a feat of strength called "you're so crazy". I'm quite sure there are a lot more. Go replay missions you already did, but in different ways then the game suggests. Quite sure you'll get some eventually. ^^
Im wondering for more specific ones XD im an acheivment ***** and will go through and get them all. I got the Mineral map FOS and then Gas map FOS wonderin about some otheres?
Killing all the zerg bases on the lava map, where the lava rises as you collect minerals, will get you a feat. That was my first feat, and got the one the above poster here got too on Welcome To the Jungle mission.
I know about those im wonderin about some other ones. SC2 wiki has two named Monster mash and hot shot but no idea how to get them.
I tried getting one on the great train robbery mission. i cleared out every terran building, and got nothing, unless one building somehow escaped my notice.
Well monster mash is easy and with a little research you can get to know about it Currently I have 3 campaign FoS, and I heard that that is the maximum - the rest should be scattered around multiplayer maybe? I don't know, that sounds a bit unlikely. Anyway, I'm a bit of an achievement ***** myself, that's why it'd be nice to know of others.
Monster mash: Spoiler On piercing the shroud, use the A.R.E.S. (the big robot with customizable weapons) to kill the brutalisk.