Left click takes or drops a whole stack. Right click takes half a stack, then drops it one at a time. Q throws one away, Ctrl+Q the whole stack. E closes.
A room is private: only its code opens it. Up to 8 players.
Every key can be changed, and the layout of your own keyboard is taken into account.
Click a key to change it. Esc cancels, Backspace unbinds.