Movement is fixed to a grid of ground and air spaces.Each turn, both players select a combat action (Attack, Block, Throw) and a movement action (Forward, Back, Jump, Stand) in double-blind fashion. Then, both players' actions resolve simultaneously over the course of a few seconds. Players are rewarded for accurately predicting the opponent's actions, and choosing the right counterplay.Attacks are the primary means of dealing damage, and cover a variety of ranges. Blocking not only prevents damage, but can also put the defender at an advantage next turn, or enable a free hit (punish) on the opponent. Throws break an opponent's guard, but have short range.Certain combinations of combat and movement actions trigger special attacks, depending on the character.Some attacks knock a player down, restricting a player's movement on the next turn. This emulates the fighting game concept okizeme.Mega Knockdown was originally developed as a card game for the 2017 season of the CUDO Plays design competition.CharactersShotokan Artist Paul fulfills the traditional fighting game role of shoto, controlling space with a projectile and an invincible anti-air dragon punch.Big Billy is a slow, powerful grappler who threatens huge damage at close range with his command grab. His strikes are slow but powerful and armored.M.M. Lewis is an up-close striker who can weave in and out of range of attacks with his Bravery Step and its follow-up techniques, or get up close with his sliding attack, Slippery Slope.Mahogany Marv is a dedicated zoner who can poke from long distance with the aid of his tree companion.Nick Beardguy is a completely average character who has no active abilties whatsoever, but he has passive skills that boost the damage output of his basic moves.Dr. Flatskin is a mid range character who can gain ground with her Fightning Feet special move, or plant a delayed vine with her summon move, Unusual Botanical. The vine covers a moderate distance in front of her, blocking far off projectiles and allowing combos in the corner.