70 hours in and 4 achiefments left to get about time to write a review i thought
this one hooked me from the start i love the cradting system it has, when i first started i played too far too fast so i ended up restarting a few times before i caught up with the crafting system turned out you should play the easy medium or hard challenges on each level you need the extra's from it too get further developed towers, as a rule i found if you can beat the hard it's time to move on (tip you can use evolution on a lev2 with a lev2 for 5% bonus effect)
some of the reviews i see are about the crafting calling it a grind i personaly find this not to be treu, i think compared to other tower defence games where you just eather win or loose here there is a sence of progress all the way to the end.
You might just be using the wrong tower i found the overhyped lightning tower to be more and more useless in later levels myself
so what do you get for your buck?
23 levels on normal mode and once completed you can try the same on heroic mode
2 250 round survival rounds in normal and heroic (these are way to easy)
a 3 tier crafting system, tier 1 can get 5 upgrades in crafting tier 2 15 and tier 3 25 (you use artefacts to upgrade stats and evolution for making towers able to goto level 2 and 3)
good quality sound and video (also enough options for me)
cons? i sat here thinking for 5 min and i cant come up with one but i gues its a matter of taste :)