For any fan of FF tactics this is a must in my opinion. This is pretty much the game we've been waiting for.
It's divided into two parts i'd say, one being the mobile game aspect, the other being the story. I'll explain them briefly because I think it's good to understand what goes on roughly. I'll also make a note about the gacha near the end.
"Story mode" (trying to keep it spoiler free): Here we have the stories, the first one seems to end up in a mercenary gang and you protect a city, you improve the city in some ways and unlock a forge, church and so on.
You play week by week and each week you get to use your crew for certain tasks, everyone has a stamina % and going on a certain mission might take 10% or 20% so you need to manage this.
You can do one battle (excluding certain story battles) a week + you can send out dispatches on mini missions like guarding a caravan, these you don't play but they tick on by themselves for two weeks, then you get paid.
You can recruit new people in the tavern, they seem to be randomly picked options and change after a few weeks making you look out for certain characters you want to fill your rooster.
You can start smithing stuff in the forge, you can rest up, train xp or skills or get a blessing and so on, lots of small stuff to do weekly to setup the town and your mercenary group.
You get to upgrade your mercenary "level" from ... i think iron to bronze to silver and so on (i presume, am at silver when writing) and each time you get the option to make the game harder by spreading the word. In addition to this there's story choices you make that are important like you need to keep order in the city for a while when the wartorn lands surrounding you is causing a flood of refugees and bandits and so on, there's choices of allying with different factions which i presume will change the story quite a lot. There's quests that if left unfinished will change things negatively for the city and others if you do them give a boost to your whole company. Basically there's a lot to do and it all feels like a great way to implement the mercenary and reputation of it into the world.
Mobile game (brief explanation at first, then the important stuff): Has classic mobile things like dailies, stamina you use to do these dailies and other things. There's some pvp you can do, there's a tower that gets harder and harder, there's gear and xp daily battles you can do too. So pretty standard mobile game stuff.
Besides that there's story here too and it can give you an insight into the "story mode" story. Like you get to see the story of how the leader of your mercenary crew ended up starting a mercenary crew, you get to see how her most trusted allies ended up being in there too, things like this.
You also unlock certain anchor points for the story mode which lets you replay it from certain points and influence the story differently, so like i mentioned before theres a few factions you can ally with. Ally with 1, play through story, then choose anchor point A to have an easier time to ally with the second faction or anchor point B to ally easier with the third faction. So it's just an easier way to replay the game and get new and different endings and so on.
Gacha: There's of course a gacha thing here. It's mostly used to influence the mobile part of the game, making it easier to beat the daily content. I did however get access to at least two characters from my mobile gacha part of the game into the story mode, so it seems you can get a little boost this way but they are still separated when you play, so let's say you're lvl 50 super-rare-gachalordhero, when you start the story mode this character will still be lvl 1 like the rest and won't have all the super skills unlocked, just their base skills (which by themselves might be really good of course). The rest you need to unlock in storymode by training or leveling as normal.
All in all, if you enjoy mobile games and ff tactics it seems to be pretty good as a gacha/mobile game but if you don't enjoy the mobile games it seems like you can just more or less skip that and focus on the story mode (spiral of destiny or something like that)
