Programming a game is
easy.
There are tons of toolkits available:
http://en.wikipedia.org/wiki/List_of_game_engines[
^].
The main difficulty is creating and designing the game "experience" and this is done as far away from a computer as possible.
Gameplay storyboarding, graphic design, level Design, Music/Sound staging, ...
Those will need to be done before even starting thinking about coding.
Max.