Mobile phones offer considerable challenges for game developers, and not least among them is the user interface, which is primarily optimized for number entry rather than for playing games. In fact, due to the limitations one of the most desirable criteria for mobile games has the design of games controlled by a one-button interface. However, this type of interface has only been seen as applicable for casual games, where mastering the interface is de-emphasized. As a number of mobile phones are starting to appear with 3-D accelerometers, game developers have the opportunity to investigate new interface mechanisms. In this article we illustrate how accelerometers provide the possibility of a no-button mobile game. While 3-D accelerometers offer a range of possible interface mechanisms, the one that requires minimal signal processing and no external references is motion, and in particular, tilt, and as such is eminently suitable for mobile phones. In this article we explore a tilt interface for a 3-D graphics first-person driving game titled Tunnel Run, and compare the user experience playing the same game with a traditional phone joypad interface and with a tilt interface in two different modes. The results show that the tilt interface was experienced as fun, and certainly seemed more attractive to players, who said they would not have played this type of game otherwise.