So far as the demo went, it was pretty good. Not sure it's mature enough to sell on steam tho, particularly not for that price.
For example, as soon as you get a few upgrades and progression upgrades in, your first girl does so much damage (I got it up to "undefined") that upgrading anything but your health is useless - but that health scales very slowly even with all progression upgrades. It doesn't matter if you do 10T damage a second, if the next boss does 30k and your health is at 25k. Also, all but the first girl do less damage for more money than her after all upgrades. The upgrades really should be reworked.