Here are two really great games for today. Both are free.
suteF
It's a cross between sokoban and a platformer. No spoilers but it is wonderfully creepy. The screenshots don't do it justice, it's actually visually charming in the same way Cave Story is. Don't let the controls frustrate you. It looks like but is not intended to play like platformer (each action is done essentially independently, so no run jumps etc.). Because of this it almost feels like a cross between turnbased and realtime control. Again, it reminds me of playing the sokoban levels in nethack.
DASH-DA-DASH
Something tells me people who like Robot Unicorn Attack or Give Up, Robot will like this. Similar over the top presentation. Completely different genre though. It's a sort of casual twist on bullet hell.