I've been playing the game off and on for a while. There are a lot of systems to contend with here, and so it definitely takes some time to learn the ins and outs of how everything works. The core game consists of races, which involves playing a few rounds of a solitaire-like game, interspersed with short sections where you have to draw lines to indicate how you want to position your horse. This is pretty solid in general, although even after playing for hours I still had a hard time getting my horse into the right position (your horse will get more energy if she/he is in her/his preferred position in relation to other horses (e.g. in front or behind) as well as if she/he is in a certain zone on the track.
The longer arc of the game is to take your trained horses and breed them to combine and strengthen their stats and abilities. This is a big part of the game, although training a new horse takes a significant amount of time, so it definitely feels like taking a step forward and several steps back whenever you have to start with a new horse. It's satisfying to gain better horses, but the whole process is pretty slow, and the mechanics don't change at all aside from some horses preferring shorter or longer races, and horses having different abilities or preferred positioning. There are special horses that pop up as options occasionally that you can pick from as well, and "winning" the game means basically training up all the special horses and winning all the top races. I ended up winning just a handful of top races and breeding just a couple of horses before I lost interest, due to the built-in "two steps back" design and the lack of variety in the core gameplay. I could see that this game would be more fun with other people to trade horses (via QR codes) with, but for now if I feel the urge to play solitaire I'll just go back to my usual mainstay, Brain Age: Concentration Training (yes, I'm still playing that game! Haha).