A late DLC to one of best games of 2016
Don't be misled by a standalone nature of this release, and a steep pricepoint. It is a 4 years late DLC mission pack to 2016 Shadow Tactics: Blades of the Shogun. What you get are three new missions, with short interlude missions that timeline was are inserted before what could be considered an ACT3 of the main campaign. Story in servicable, character as enjoable as they were in the original, but it's not what I would call a necessary or significant expantion of the main storyline.
Some Quality of Life improvements are missing when compared to Mimimi's more recent Desperados3, though it's nothing I can't live without. Aiko's Choice runs on the same engine that original Shadow Tactics did, so no improvements were tranfered over from Desperados3.
If you didn't play base Shadow Tactics:BotS, you should play that first, before considering Aiko's Choice (and perhaps Desperads3 - both will give you far more bang for your buck or other currency of choice). If you did, then you probably know by now, if 3 extra missions is something that interests you, and what is the pricepoint that you are willing to pay.