Rubber should have been a short film: twenty minutes, tops. The mildly amusing idea of a tyre that can blow people's heads off with its psychic powers has been stretched way beyond its limits. A short could have packed in all the good bits and even then it wouldn't have been great. Okay, but not great. The sequence where Robert discovers his powers is oddly engaging. But from then on it goes steeply downhill. Not the tyre, the film; that would have been too exciting.
The writer/director obviously knew the script was lacking in story substance so he tacked on really irritating scenes where the characters are aware that they are characters in a film. Metafiction can be okay at times - The Cabin in the Woods is a prime example that I did actually enjoy, although I can't say that I'd want to see it again - but in Rubber it only serves to highlight the lack of any real events.
So are there any plus points? Robert is a convincing character even though he is a tyre. Scenes of him rolling through the desert bring to mind Fata Morgana by the legendary Werner Herzog. Depth of field is used effectively to create some strangely beautiful images. The effects are well done with heads exploding seamlessly. Wings Hauser (Mutant) is in it, but gets virtually nothing to do except look through binoculars.
An initial fourth wall breaking scene goes on and on about how there is 'no reason' that most things happen in films - to extend the running time this scene is replayed at the end but from a different camera angle - justifying why a tyre comes to life and blows people's heads off. I didn't need to be told this. Create the rules and I'll go with it, regardless of how stupid it is. As for why anyone would want to watch Rubber... well, there is 'no reason'. (And yes, a smug head wobble was included in that last sentence. If the marketing department are able to crack terrible jokes on the poster, surely I'm allowed one too.)
If you like this you could also try:
Hobo With a Shotgun, Tucker and Dale vs. Evil, Planet Terror.