mostly science... since technology is the application of scientific knowledge for practical purposes...
Game creation is not the application of scientific knowledge towards any end, neither is most forms of innovation, and creation of things new. It is an art, because the creation is done by intuition of the designer, and thus is art. Now, you want to talk about actually producing a game, well that also has some technology, but the core innovation concepts is art, done by visionaries. The thing about games is that they are not practical purposes, but toys for entertainment. Entertainment is a very subjective thing, that is hard to pin down, and excessive use of the same patterns leads to boredom, which makes it hard to replicate. The fact the videogames industry can't be predicted to any certainty what will be the next big hit, and follow standardized methods has resulted in stupid concepts people don't want in the end (Dead Space is now dead, in part because marketing types, using scientific methods determined the game HAD to have multiplayer).
While one can find a bunch of science behind games, the spark of genius that makes something stand out, is art.