3. Snake Beater - Metal Gear Solid HD Collection
You're still in a dreeeeeeammmmmm.....SNAKE BEATERRRRRRR!
For Solid Snake, he's usually pretty dedicated to the mission. After going through the wringer in Shadow Moses, beating Metal Gear Rex and fending off his brother Liquid after seemingly killing him umpteen times and failing, his next mission is infiltrate a tanker and find evidence of a new Metal Gear.
So imagine our surprise when Snake manages to find the time during the mission to take a quick break, unleash his Solid Snake and give it a good old beating.
To get this one, Snake needs to find a locker. If you open it and find one of the risqué posters the developers put inside of Japanese models, you can then switch to first person view and start looking at the girls in detail. If you call up Otacon after that, you'll witness a truly memorable scene where Snake appears to be relentlessly beating his other snake to the poster.
Seriously - the look on his face is a sight to behold.
This was available in the original Metal Gear Solid 2, but it's only in the HD collection that the achievement was added.