The game starts out fun but a bit past the halfway point when the opponent starting points start becoming worth multiple yakuman it turns into a grindy chore. Also, do not be deluded for a second that knowing mahjong strategy helps, as the game gives the characters a luck stat which directly rigs the game in their favor. I've seen more yakuman in an hour of this game than the rest of my life and I play a lot of mahjong. And raising that luck stat involves grinding currency that will see you repeating a lot of the earlier matches.
Also, the luck system is kind of stupid in that it only seems to consider pure tile efficiency, which means that if you have high luck and are trying to do something like chinitsu, you'll constantly get anything but that suit because technically having tiles in all suits will increase the number of tiles your hand accepts. Well okay, playing pure efficiency instead of high value hands wouldn't be so bad if it wasn't for the fact that you have to deplete the entire pool of the opponent's points, a pool that may be worth multiple yakuman. Good luck chipping that down with tanyaos. While we're at it, it takes a big grind to get your own starting points even above a single mangan, so while you have to whittle down the opponent's massive points pool, they will quite often kill you in a single round.
Then there's the wall rigging mechanism that can guarantee you a specific starting hand, which is as powerful as it sounds. The problem is that using it, again, requires you to expend a resource you'll have to grind for tens of hands for even just one use. Oh, and the opponent can use it too, except of course they have no cost for it and can literally start out with 1-shanten to tenpai hands every single round if they so choose. Fun.
The game also has some unorthodox implementations of riichi rules. Swap calling is allowed so abuse that to your heart's content. The help menu has a page titled "Furiten" which does not describe the furiten rule nor does it appear to be in play. You'll get money bonuses after the match but I have no idea if their description actually matches when they're given out because every time I don't win with a yakuman I get a bonus for "winning with a yakuman" and every time I do I don't get the bonus... There are no points awarded for being in tenpai at ryuukyoku and the 2 player format makes games very short so you can easily go tens of rounds without any points exchanges which can get a bit boring quick.
Tl;dr: It starts out fun and slowly spirals into sheer frustration. It's not really a mahjong game but an RPG grinding game where you raise a luck stat to win games that on the surface look like mahjong.