Lava waterfall looks cool as it is, but personally, I'd like to see a hint of orange, perhaps bits of yellow in places, using more general warm tones and not just red. You know, like real lava. It would also help to really pronounce its... Dangerous... Fieryness.
What Mathias also said about the top and bottom waterfall tiles being one and the same is rather true, actually. Doesn't really make the vertical movement, that is to say the flow from horizontal to vertical that obvious. While lava is, of course, not as fluid as water, it's still fluid. Upon further reflection, just where is the lava-fall coming from? The wall? Doesn't make much sense, but I suppose this is all just a placeholder position.