The art was very cool, and the upgrade tree was a nice touch along with the sleep system to pass the days. Day 1 was easy, then I bought an upgrade for Delivery missions and another for E rank missions, and after that I spent several days with no gains as I either had none of the symbols needed and the wheel was only red and black, or I had only 1 symbol so the green area was very small.
Had to restart and avoid buying new options until getting enough points to buy other upgrades.