#11 - Pikmin (Kudos to S.Peelman for guessing this)
I often say things like "this game was a massive surprise for me" about things on my top 50, because they often exceed my expectations which may have been pretty low going in. Pikmin 3 is the ultimate "surprise" game for me. I had no idea what to expect going in as it was a title they'd thrown in for free to try and convince me to buy a £30 pre-owned Gamecube, yet it turned out to be one of my favourite games of all time.
One of the things that made it so great is that it just felt so different to everything I played before it. I really felt like I was exploring an alien world when I first controlled Olimar, even though it was just Miyamoto's back garden :P. Things like controlling the Pikmin, which is a little big rts; little bit action game was just completely new. Even the premise - scavanging parts of your ship while breeding new Pikmin to control just felt like something I'd never really seen before.
It all just worked so perfectly together that Pikmin really earned its #11 spot on this list. Sadly, the sequel couldn't live up to the highs set by the first game, but I remain a fan of the franchise to this day and Pikmin 3 is one of the biggest swaying factors in buying a Wii-U for me. That's how much I love this series; all pretty much based on my love for this first game.
Fantastic soundtrack, too.