Master the blocks, as well as all the other players, in Gunbox, a game as much about building as it is shooting.
How to play gunbox.io
Move with WASD or the arrow keys. Select inventory slots with 1, 2, 3, & 4. Earn points by blowing old old blocks, players, and monsters. Pick up block types littered about the map in order to build yourself a shiny fort.
You can easily farm the NPCs to grow in power without having to deal with other players. The map is big enough for that.