There really aren’t enough lines on Mini Metro. Running out slows the game down a TON. So, more lines could be added to make the game a bit longer. Here’s some color ideas: Purple, Orange, Gray, Black, Light Green. These alone would enhance it greatly.
Fun fact! All of our colours are based on the colours for each of the cities metro systems. We stick with 6 or 7 for two reasons. The first is because it makes the game more difficult and it’s that difficulty that makes the game interesting and challenging. It would have the potential to extend the game a bit, but I don’t know if it would make a huge difference in the actual game play. Those that want to keep playing can always do so in Endless Mode. The second reason is that we anymore than that and things start to get cluttered (especially on mobile). We wanted to keep things clean and easy to read, and seven seemed to be a good number.
Fair enough. Boston does have purple and gray lines though.