We just finished it with the "secret ending". Such a beautifully made game. Such deep environments and good puzzles. Very well made (doesn't crash or choke). Great controls (very fluid and intuitive). Very creepy and yet beautiful and deep -- and philosophical. Played it with my daughter and we both loved every minute -- just handed the controller back and forth the whole time.
I wanted a train management game... I played Train Valley, but honestly, I just find the UI and overall design clunky and cheap. Mini Metro on the other hand is super clean, super minimal, and VERY well designed. And it has a cool modular synth vibe. The trains moving, and the people arriving at the stations, each has a little pitched sound that goes with it. so as you build up, it gets more and more layered. Just beautiful.