I played this game for more than a year ever since release, and I have to say, I hate tower defense games, but who knew adding waifus to the game would make it exponentially better.

The story gets better the more you go deeper into it. Honestly, its mechanics are pretty dang nice and cool and I like how they add a twist every event. Contigency Contract is a great defining event that can really tests skills and units. As long as you don't consider the gacha aspect of the game, you can pretty much playthrough it and have fun strategizing (or copying strats on youtube/bilibili).

Unfortunately, I had to stop playing this because it got tiring eventually. Normal banners are forever 50-50s without spark (100% after certain amount of pulls). Which means, you can go 500+ rolls and if your luck sucks, then you simply won't get banner character at all. Limited banners do have spark but they reach all the way to 300. And in a game that barely gives any rolls to begin with, that's pretty bad. I don't really care if other people say I got X in only ___ number of pulls. Because at the end of the day, it's luck. It's not calculable, therefore it does not matter.

Don't let this ruin it for you to play it, however. Definitely a game worth trying, especially if you don't care about pulls.

The mechanics and graphics are simply amazing. The story is about average, and the gacha currency-rate-pull ratio is godly good.

Only 15k currency to reach spark, release banners don't have other S-constructs spooking you, and you get 5k of the currency every month. Each new S-rank banner appears every 2.5~ish months and lasts for an entire month, so having a monthly card definitely helps. People who don't play gacha games often won't understand just how good the currency gain relative to banners are.

The game is played as a side game due to stamina/serum being limited, but overall, it's one of the best gacha games I've ever played.