I actually played a demo of Spectromancer a few months ago, I think. It seemed shallow, but it was just the demo so maybe when you add in the deck building it gets a bit more interesting. I'll look into it...
Greed Corp looks interesting -- wish it had a demo.
I did play Frozen Synapse on a friend's computer. Thought I'd love it, but ended up indifferent. I'm still not really sure why.
And I own GSB.
Thanks for the suggestions though! More than I thought I'd get.
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No amount of planning will ever replace dumb luck.