game.World.prototype.collide = function (a) {
    if(a.collideAgainst != 1 && !window.canDie)
        return false;
    if (!this.collisionGroups[a.collideAgainst]) return;
    var i, b;
    for (i = this.collisionGroups[a.collideAgainst].length - 1; i >= 0; i--) {
        b = this.collisionGroups[a.collideAgainst][i];
        if (a !== b)
            this.solver.solve(a, b);
    }
}

function toggleInvincible() {
    window.canDie = !window.canDie;
    jQuery(".invincible").text(!window.canDie ? "Disable Hack" : "Enable Hack");
}

jQuery(".game").append("<div style='position: absolute; left: calc(50% - 170px); top: 0'><a onclick='toggleInvincible()' class='invincible'>Toggle Invincible</a></div>");

for(var i = 0; i < 2; i++)
    toggleInvincible();