I loved AI War, and so just bought Tidalis last night. I only got through the tutorial and a couple rounds of the campaign, but so far it seems like a cool game! The gameplay is truly interesting, and the whole game is permeated by a level of polish.
While I'm at work and unable to play, I was wondering - what do the collectibles do (tires, etc.)? Do I spend them later somehow, or can I later use them to craft things, or are they just completely pointless except for the goofy fun factor?
