I'm having glitches on more than one computer where movement doesn't work for some reason. I usually restart the page, but that doesn't always work. If you could look into this, that would be amazing.
One of the best things about Kong is that you can check the "new games" section, check out a brand-new game as the 4th player so far, then check back later that day and see it under "hot new games" with 32,000+ plays. (Oh, and the game is great too. 5/5 and favorited.)
Sorry for the double comment, but also, it would be awesome to tweak your hero's and creature's behaviors. It could be called "training," and it would let certain creatures have priorities (strong creatures against a boss, or weak creatures against other weaklings), when to retreat (there could be a checkbox for "complete attack script before retreating," for instance) and other such things.
I just beat level 10 on my first try. It was one of the easiest levels in the game. If you're strong enough (through a careful blend of patience and paranoia), you can bring the castle down to almost zero before the dragon shows up, and then it just takes a second or two to beat. You should send the dragon out sooner and have stronger enemies before then, too.