hello tacoman, ther 4th character is not available right now
the demo only got 3 playable character, we will add more character for each new stage
I found a glitch where you could play the 4th character. if you select multiplayer and pick the miner (4th character) with one and something you have unlocked with the other you can play it. ( it only works if you have the locked character as the first player and the unlocked as the second eg. P1 = miner P2 = knight)