I would like to know if it's possible to just place 1x1 block in this game. Each time I place a 2x2 block, I have to use my pickaxe to remove the exceed I don't want. Is it possible ?
Holding shift limits the effect of the tool you're using to a single block. This includes placing blocks and destroying blocks, foreground or background, even with tools such as the pickaxe that normally affect larger areas.
Holding shift will reduce the size of your matter manipulator to 1x1 until you stop holding shift. This affects placing blocks as well as breaking blocks. I'm not sure if it affects pickaxes.