The main selling point of this game is, in my opinion, the music. The OST is really beautiful and really fits the cutscenes they're played in, making the scenes so much more captivating, although it's just pixel art. It also adds the fantasy-like atmosphere to the game.
The combat gameplay is decent, it's pretty basic and easy to understand. That's why it might be a little repetitive and boring for some people, but I, to my own surprise, quite enjoy it.
Outside of combat, you get to explore and find chests, which is one of my favorite aspects, I just love exploring and doing puzzles to get extra rewards. I also find it unique that technically, the stages are also like a second main lobby, and that you're actually staying in the world of the stages (the 'stages' are actually connected and are like another system like a tower or a world) when going into the next stage.
The bad part of the game would be the storyline...well, I can't really say it's bad, it's just not that good (imo). The story starts like any other RPG, during the stages the main story feels completely disintegrated and when there is some, it's as predictable as it can get, the villains have no personality, aren't given any reason to why they act like they do and we just kill them because they are villains. I might have exaggerated a little, but that's just how I felt reading the story. But well, nobody other than me reads the story of a game anyway lol
Personally, I don't care about gacha because I'm just a casual player, but I think others might. So I'll say something about that too:
The first thing worth noting is that the game has a built-in reroll mechanic. For the first time you roll, you get to reroll a maximum of 100-times for free. Within these 100 rolls, you can confirm a roll you think is good and get it as your 'first roll'. After you've confirmed, the 'first roll' is set, you ge the stuff and you have to invest to roll again, like other gacha. If the rates on the reroll-roll are the same as the normal gacha, then I gotta say it looks really painful wth.
Now there's probably still one question you want to ask: Is the game F2P-friendly?
Well...yesn't. To answer this question, I actually got myself to ONLY play with the characters that are guaranteed for every player/first ones you get and see how far I could go. I got stuck on a stage in chapter 2 (it wasn't even the boss battle), although my characters' levels far exceeded the recommended level. When I switched one of the characters to the UR character I got in the gacha however, the battle went like nothing happened. So, what we can conclude is that the game is a little meta-based, seeing how much of a difference a single character switch makes, but since there's the reroll mechanic, anyone should be able to have a good character.
Overall, I do think this game is enjoyable if you don't mind the gacha aspect (and the storyline but leths be honest, nobody cares). I hope you'll have a good time playing the game as well.