itch.io

Well, this have been fixed on GitHub. Here's the snippet I used to make it working, if someone else ever have the issue:

// iframe-fix.js
var lastTarget, canvas, body;
window.onload = function() {
  body   = document.querySelector('body'),
  canvas = document.getElementById('canvas');
  var activateCanvas = function (event) {
    lastTarget = event.target;
    window.setFocus();
    console.log("Set focus on window");
  }
  var preventScroll = function (event) {
    var keyCodes = [ 32, 37, 38, 39, 40 ];
    if (lastTarget != canvas) {
      return false;
    }
    console.log('Key pressed: ' + event.keyCode);
    if (keyCodes.includes(event.keyCode)) {
      event.preventDefault();
    }
  }
  var handleMouseDown = function (event) {
    window.focus();
    event.preventDefault();
    event.stopPropagation();
    event.target.style.cursor = 'default';
  }
  body.addEventListener('keydown', preventScroll, false);
  body.addEventListener('click', activateCanvas, false);
  canvas.addEventListener('mousedown', handleMouseDown, false);
}

Simply include this script at the end of your other scripts call ;)