Indeed. There are, roughly, three stages of games being announced:
1. Very early game. Too early for feedback to be much use beyond "Keep at it!"
2. Mid-development. Keen to accept ideas and look at ways to improve whilst the game is still malleable. This is the main Incubator target group (though not all will have the needed time to take part).
3. Late development. Mostly bug-fixing or content addition. Releases are iterative rather than game-changing. These can benefit from Incubator involvement, but may prefer to concentrate on polish.
Paul: There are no restrictions on the type of game here. Just be aware that you might get less feedback (or less useful feedback) from people who are primarily interested in turn-based games.