Instructions for gameplay are in the game, but that red bar thing at the top of the screen is volume control. The switch next to it toggles the floating labels for the players. You'll want a friend to play this with for the best experience. If you want to remix this to add art, feel free to use the pre-remixed version by VeryTallRose, in which everything's a template!
I've been working on this for a while, and I'm happy with this! Full screen is best screen! Please report any bugs you find, and I'll try to fix them in the next version!