If there is an award for cleanest design to achieve it’s goal, Mini Metro wins it. When you first load the game up, you are taken directly into the first map. No intro screen, no main menu, no tutorial section; just right into the game (with tooltips to help you along). And it works, because Mini Metro is exactly what you would expect it to be; you connect stations and transport people (well, symbols, more on that in a bit).
Things start nice and slow, three stations, low population. As the game progresses, more and more stations pop up in random locations, and you are given more trains, train lines, tunnels, and other bonuses to build your network. You lose when any one station overflows with people.
Each station in the game has a symbol, and the train raiders in the game are also symbols. A square ‘person’ wants to go to a square station. The odd/unrealistic part is that any square station will do, but once you know this, you can more fully begin to build successful setups (I was initially expecting people to want to go to one specific station, so my early designs failed horribly). The other negative is you can unrealistically min/max things without issue; you can for example pull an empty train from one line and place it directly on a station that is busy, have it deliver what it needs, and pull it off again. Same goes for train lines; delete or edit them as much as you want, instantly, with no cost/penalty.
That said I’ve been able to ignore those faults and still very much enjoy the game as a fun puzzler. It’s very easy to pick up for a couple tries in say 30 minutes time. There are currently plenty of different maps, and the replay-ability is very high per-map due to the random nature of it all. For its usually discounted price of $5, its a worthwhile pickup.