It does not matter that a demo would become obsolete. Don't even call it a demo for that matter, release a striped down beta build and claim it is the "free alpha" of the game game (aka creative mode in Minecraft) and leave it up forever.
Games with this many units can go either way. It can be fun and epic and chaotic, or it can just be a zerg fest. No one here knows which way it will go and I don't think many people would put down more than 5 bucks for a completely unknown comoditey.
For everyone talking about needing a Demo, just go check out Attack of the Paper Zombies. It's the same game, minus a few weapons and fancy graphics.
True enough. The game is much better now, but Paper Zombies is the grand-daddy of Infested Planet.
This is a very very bad selling point. Now you have to convince everyone that the features you added to Infested Planet are worth the cost difference.
Finally, offering a full refund is cool, but that is still a lot of work to put people through. We still have to do all the crap that comes along with paying for your game. I am lazy, I admit it. But working through what ever payment system you use and then doing what ever it takes to get my money back seems like a lot of work for a game I may only play 5 minutes.
Indie developers can miss a lot of things that seem small, but knock a game down from "Fun and playable" to "Fun but work". I think I can speak for many people when I say "I have no idea what you missed, and I don't want to spend 15 dollars or even 30 minutes of my time to figure it out."