How polished and playtested should new Icehouse games be before I post it?
It is generally considered polite to do at least rudimentary playtesting on your own — first by yourself, then with a few local friends. You will want to make sure the game is not trivially unworkable before posting it here, if only to avoid embarrassing yourself. Also, people will not pay much attention to a game that has not been playtested at all yet.