When Joaquin Phoenixs character in Her isnt wooing his smartphones operating system, he spends much of his time playing a video game. Its an impressive and imaginative concept for a game, dreamed up by artist and animator David OReilly, who has decided to follow up that project with his first real video game. Its a surreally relaxing experience that sits somewhere between a screensaver and a traditional video game. I don’t think Mountain needs to be explained, says OReilly.