Hungry Yeti Achievement
Eat 50 KGB Agents with the Yeti.
You’ll meet the Yeti during Russia during 2-2. He’ll be chained to 2 stumps and you have to free him to use him. If you stand in the one position there will be a constant swarm of enemies attacking you and eventually you’ll get the achievement. Make sure you eat the 50 KGB Agents before the tenth sentry-tower as the Yeti will arrive at a cliff and you won’t be able to use him anymore.