15 Impossible Xbox Live Gaming Achievements Nobody Unlocked

15. Aperture Science - Portal

Portal's a glorious little game, a physics-based puzzler that'll really make you re-evaluate your position within any given game world forever more - and although its infectious take on spacial awareness was addictive, getting this Aperture Science accolade to pop was more like a force of will to carry on that anything else. One of those 'sounds easier than it is'-type deals, you need to get all Gold medals in all challenges. However when the requirements for such range from sheer amount of physical motions necessary to complete them to some very tight time limits, it makes for a challenge that only a minuscule fraction of the entire populace can say they overcame.