[Browser][2012-2016] Multiplayer 3d first person shooter blocky zombie game

Things i remember:
It was first person and multiplayer
You had a variety of weapons
The game was blocky, the maps where made of blocks like minecraft (i think)
The characters where a little smoother but still blocky and had big heads
The game had a tutorial level teaching the mechanics
I am 75% sure players could create maps but i am not sure
Probably it was some kind of game that didn't take off and the servers are not up anymore

(English is not my first language so i am sorry for any mistakes)