With Zero Charisma, the subculture of tabletop role-playing games gets the crowd-funded indie movie it deserves. And of course that’s a back-handed compliment, but fitting for a film whose appeals to a general audience include withholding mercy from its anguished and anguishing characters. Anti-hero Scott (Sam Eidson), a tubby and tyrannical gamemaster, understandably clings to fantasy when reality means sharing a shabby house with grandma and working at the “Donut Taco Palace II.” Tantrums ensue when Scott sees his de facto coterie of pitiful geeks invaded by Miles (Garrett Graham), a nemesis with threatening talents, actual social aptitudes, and a pretty girlfriend. Directors Katie Graham and Andrew Matthews want to dramatize, and laugh about, the high stakes of a real cultural shift; theirs is a movie about how old-school nerddom reacts to colonization by hipsters. It is a nice touch that when Miles first comes over to Scott’s place, they can’t figure out whether to bump fists or shake hands. But the piled-up scenes of Scott being a dick and being humiliated bring diminishing returns. The casting is spot-on, but there’s some roughness around the edges of Matthews’ script, which the performers’ authenticity only exacerbates. But then, awkwardness always was a part of the game.