It probably doesn't look realistic, because a planet wouldn't be existing that close to a black hole to get that sort of effect.
It would be at best orbiting at an incredible speed, and likely undergoing huge amounts of tidal forces, to the point it was quite literally stretched out, or ripped apart.
In regards to the lensing effect, while we can't do it computationally perfect, the effect is as reasonably close to accurate as we can get in a realtime rendering situation.