IMO it would also be a good idea to set funding levels goals when starting the project. It would give a reason for supporters to know what to push for.
For example:
- 300K: gets 20h of game done, IE engine is used, Interplay art assets are reused (license), no voice acting
- 400K: polish, gets partial voice acting, 35h of game
- 500K: more game, better game, more polish, additional ways to solve things, more non-linearity, more characters, more endings, more replayability, etc
- 1.5M: ToEE alike engine/art, all of the above
- 2.5M: you win the internets
This is just an example and do