was curious if there is one, i didn't unlock any when playing through the campaign

Haven't heard of any.

Yeah but.... It's a secret

PM me it, please.

I'd imagine there would be.

No. If there was you wouldn't get the achievement for beating the final mission. They did that with SC2 WoL.

That's completely false. I didn't do the secret mission in WoL in my first play through and got the achievement.

slapping them rands down

those mission dont belong to the campaign

i think its feats of strenght achievement

they dont even give you achievementpoints

there was an achievement for completing the secret mission in wings of liberty, that is kind of how i discovered there was one...