Jerry Trainor, who plays Cosgrove's older brother on "iCarly," and Jennette McCurdy, who plays her best friend, are the leads here. If the world they inhabit is a little more dimensional than that which their sitcom portrays, it will still behoove adult viewers to forget what they know about how things actually work, and forget also the many other movies and sitcom episodes that have been fitted to similar carriages. (Including, see above, "The Lady Eve.")
Long and floppy, Trainor plays thirtysomething child-man Quincy, known as Q in the world of multiplayer video games, in which he is a superstar. He has apparently not thought to monetize this fact, as he still inhabits his parents' basement and delivers Chinese food for not quite a living. When his folks announce a move to Florida ("It's what the aging do," his mother says), Quincy, loath to lose his perfected gaming environment ("I have very specific lighting needs") determines to buy their house. There is, conveniently, a contest with just the right amount of prize money and less conveniently, a talented opponent, who turns out to be Chris (McCurdy), a teenage girl Quincy sets out to sabotage.
Quincy is both hero and villain, although it's never in doubt that the villainy will be swallowed in some final heroic gesture. Along the way, there's a good bit of farcical lurking as Quincy, incognito, dates and falls for Chris' mom (Janet Varney, looking more like an older sister) and masquerades incompetently as a home economics teacher. ("Teaching is exhausting," he admits. "You have to know things, which is very difficult for me.") His class includes all the young principals in the story: the jock, the nerd, the mean girl and our heroine.
Chris has no friends, but this seems as much a matter of economy as of character. Black leather jacket, bad attitude and video-game mastery notwithstanding, she is required to stand for the imagined conventional aspirations of the girls in the crowd — she really would like to go to the prom with that cute football player (Jean-Luc Bilodeau). There is a nerdy boy who likes her, but the usual math applies: Pretty people get the pretty people.
Such moral as "Best Player" offers is that there's more to reality than virtual reality, but that while maturity does sometimes mean having to say you're sorry, it does not mean an end to fun. The kids can rest easy.