Three Scientific areas of researching Videogames
a) Game Design "is the process of designing the content, background and rules of a game" at wikipedia.
"...conceiving and designing rules and structures that result in an experience for players" in The Rules of Play (2003)
Big concerns, analyse and develop new forms of gameplay and interactivity.
b) Video Game studies "is the still-young field of analysing video games from a social science or humanities perspective." at wikipedia
Big concerns, analyse textual and cultural meanings present in videogames. Special approaches at the moment are ludology and narratology.
c) Game Programming deals with programming and can "include advanced physics, artificial intelligence, 3D graphics, digitized sound, a custom musical score, complex strategy and may use several input devices (such as mice, keyboards, gamepads and joysticks) and may be playable against other people via the Internet or over a LAN." at wikipedia
Big Concerns, studying new forms of programming and new harware in order to deliver always the most powerfull capacities for graphics and AI.