I've seen some puzzle games unlock their levels in groups of similarly-difficult levels. Rather than linear unlocks, this game could benefit from something more like that.
Univern72: remember to take into account space savings and range increases. It is easier to defend a few larger, but tightly-packed structures than it is to defend a bunch of smaller ones. There's also the fact that the "power lines" between structures and energy sources take up space as well.
Evi1M4chine: the ±0 genes can be useful when you're bottomed out on one or another ability. It basically cancels out the negative effect, because you can't go lower than rock bottom.
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