Neko Gurashi no Gamer-san

Meet Riko, a twenty-nine-year-old office worker with an obsession with video games. Her coworkers can't quite figure her out—she never talks about her personal life, she never works overtime, and she never joins them for happy hour. Is she antisocial? Nope, she's rushing home to play video games alone. That is until a stray cat is found in the office parking lot and ends up coming home with her! Having no experience with pets, Riko uses lessons drawn from video games to guide her in cat care, while her cute companion tries to understand her behavior through a cat's worldview.
(Source: Dark Horse Comics)
Note: Includes 1 extra chapter.