Thanks, glad you liked it.
They were fairly easy to create, I made a Unity cube which I stretched with 2Y, then I used 3 materials (which is bad for optimisation or so Unity tells me), 1 standard Unity color, another material I used a transparant PNG with a handdrawn square on the sides which apparently when applied to a basic cube gives it this edge effect, and another material which was also a transparant PNG with some handdrawn random lines to create this grungey effect and that's it, never done graphics before but I guess it turned out ok, the eyes are these circles which come with Unity, that I have turned to make them look happy or sad.
So yeah, most graphics are just standard Unity cubes with those 3 materials.