2D stealth perfection
When Mark of the Ninja came out, it got a lot of positive attention. Klei was well-known for the Shank games, but Mark of the Ninja was supposed to be head and shoulders above it. I bought it and played the first level, and promptly put it in the backlog for something else. That was a mistake. It's an incredible stealthy 2D platform/action game. It easily does some of the best representation of senses that I've ever seen. Line of sight, smell radius, and loudness of sounds are all perfectly implemented. There's a fantastic mission 2/3rds in where you're sent to assassinate someone. As you get closer to killing them, the music is building in parts, and it really feels like you're the cold hand of death closing on their throat. It nails that feeling of striking from the shadows and disappearing into the night.