Interesting. These seem to strike a balance between Apple's decidedly glosss-but-normal-shaped emoji and Google's flat-but-ghost-shaped emoji. I'd say that we really need an open emoji standard, but we all know how that goes.
There is room for interpretation to what each drawing will look like in each implementations. The standard simply says something like: "Cloud With Lightning"
Until this moment I have always wondered why Google chose to use poo-shaped emoji...