It should tell you something that the Steam listing for Dennaton Games’ Hotline Miami ($10) requires an age verification: this one is not for kids. The top-down shooter might look a bit like Grand Theft Auto II, but it’s even more violent and vulgar. Set in 1989 Miami, you control a character on a rampage, but unlike most games, you’re not more resilient to your enemies’ attacks than they are to yours; one hit kills are a big…