Incursion

In Poker Squares your goal is to place 25 playing cards (from a deck of 52), one at a time, in a 5x5 grid. Your goal is to make the best ten (or twelve) poker hands, five horizontally, five vertically, and optionally the two diagonals, scoring as many points as possible.

Endless Swarm is an XNA community game available over Xbox Live Marketplace. It is a tower defense game.

Competitive sudoku.

RBR - Fading Memories is the first game from developer NiKo MaKi.

Little Strategy is an Xbox Live Indie game.

Control gravity and negotiate your way through a series of increasingly difficult puzzles!

Don't Fear The Sweeper is an XNA community game

Go 3D is an XNA community game

Red Invasion: Tower Defense Blitzkrieg is an Xbox Live Indie Game.

Fall Down pits the ever-opposed forces of Red and Blue against each other in an ultimate battle to capture scrolling platforms! The first player to fall past a platform captures it and scores a point. Taking time to collect power-ups can give some advantage, but taking too long only results in death at the top of the screen. Watch out, because as you progress, the platforms slowly accelerates!