Beeing original with a game idea does not mean to
ignore "standarts" like the user-inputs / keysettings in
AAA Shooters.
People expect a game to be easy to handle, playing the game
not "working" the game.
So if someone makes a shooter-like game, dont! try to
invent the weel again and make some akward key-settings.
or you have it freely configururable.

High FPS are also more important than having
top noth GFX.
And dont bother the player with a flat story
if it is of a "John Parker, an ex police man freeing the world of the uber-evil guy XYZ".
If the story is not really key point to gameplay, dont try
to emphasize it too much, and just present a simple version
of it to the player.


And.. the fist 10 minutes of the game are key to the rest
of the game, as the beginning of a game is remembered longer
than some part in the middle.
The player should learn to controll the game in this period
and have some rewards to get him going.