Except Fez is kind of 3D, I guess
The second day of Microsoft's annual end-of-year games sale puts 2D explorative indies in the spotlight. Terraria, Fez, and Spelunky are all on discount for approximately $5, $2.50, and $3.75 respectively. These are only the daily deals, as there's still the list of offers that run until December 23.
Spelunky is a favorite around here, so it comes highly recommended by most. You could even see if you can equal Jordan in clearing Hell. Actually, let me save you some time -- you probably can't. Or, if you're feeling really ambitious, you could play Fez to prep for Fez 2.
Countdown to 2014 Daily Deal Day 2: 2D Modern Classics [Major Nelson]