Just have been addictive over a browser game called Attack on Titan/Titan Slayer. Basically you choose a map, and a character based from the anime/manga that I very much adore. Not much in it but it's still in progress with updates to come.
Basically you kill titans in the area you have been thrown in. And there is a timer that will depict how long it took you to slay them. Like a beat-the-record game.
Here for me, I chose the forest map and the character Levi
(most badass motherfucker in the universe.) and decided to mess around with him a little to show how the game really looks like.
(ps. a titan won't die except getting a fatal strike on the nape of the neck. that's it's only weakness to get one down.)
Just spawned at the ''Forest of Giant Trees''.

Moving in to attack the titan.

And down it goes.

Here is the link to play it:
http://fenglee.com/game/aog/Enjoy.