I'll start with a few of the things I disliked about it... namely, that maps are all-or-nothing. Either you win and get rewards (you hope), or you lose and get absolutely nothing. Related to this is that there's no way to practice maps. The result of both of this factors is that when going into a tough map, rather than test out strategies it's best to just look up a guide, and then it becomes a matter of trying to follow it as best you can... which can become frustrating if your units aren't exactly the same.

I'm not a tower defense wizard or anything, and to me the fun part of Tower Defense games is methodically trying new strategies and figuring out what works on my own. This game takes that away from me. Either the maps don't really challenge me, or they stump me and I just look up a guide because I can't waste stamina and charisma on trial-and-error. I'm normally fine with slowly figuring things out, but when you lose resources with each attempt, it just becomes frustrating - particularly since Aigis is the kind of game were variations in units, placement, timing, and even order can mean the difference between victory and defeat. There are a lot of ways to go about an Aigis map, and on the toughest maps only a handful of them result in victory.

Another issue I have is that if your browser/computer crashes, or you lose power or internet, you lose that attempt... although that's more of a issue with the way the game handles that, than any issue with the game design itself.

As for the things I like about the game, that'll take a longer post. I actually have thought about what I'd do if I were to make an Aigis-like game, though since I have no artistic or programming expertise, those were just idle fantasies...