The crafty but ultimately disappointing “It Ends,” which just premiered at SXSW, takes a familiar experience and throws into a cleverly existential horror premise: What if you were driving on a deserted, tree-lined road in the middle of the night — an already eerie scenario that plenty of filmmakers have used to freak people out — but the road just never ended? What if you just kept going and going for thousands of miles?
There are moments throughout Alexander Ullom’s debut…