At launch, Killer Instinct serves as a solid foundation for what could eventually become a good fighting game. More characters and stages are coming down the line, but at launch, the game's limited single and multiplayer modes are glaring and will grow stale quickly.
South Park: The Stick of Truth suffers from overly simplistic RPG mechanics, some iffy design choices, and some major bugs. In spite of all of that, the story nails everything that make Trey Parker and Matt Stone's television series such a joy, making this an ideal choice for South Park fans... and likely South Park fans only.
The Yoshi's Island series is one of my favorite gaming series ever, which is why it's so painful to see Yoshi's New Island fall short in so many ways. It's not a bad game and certainly a serviceable one for younger audiences and new players. Unfortunately, for those that have followed Yoshi since his first starring role nearly 20 years ago, this game is a tremendous disappointment.