There are a few things that make it immediately clear a video game is broken- when a level is unbeatable, when glitches make the game unplayable, and when a game sits and plays itself.
That last one is the rarest of the three because it actually takes more work to muck your game up in that way, since the bit going haywire is the non-player character AI added to make the world feel more real.
The new game Just Cause 3 apparently has its NPC AI set to "go crazy whenever player character stands still", because standing still turns the street into a bloody nightmare in less than two minutes.
Not sure how the rest of the game plays out, but this video by ThingsWePlay proved Just Cause 3 is a great game to turn on in the background while hosting a cocktail party.
-Via MemeBase