Citymapper is clearly created by a team of people who love paying attention to detail. Let's take a look. First up is a minor one: The settings cog has a smiley face in it. It reminds me of the sun, which might be intentional.
When you look at the map view from the home screen, the zoom levels are not abstract, but based on walking distances.
At the bottom of the home screen you can see a group of friendly people. As you scroll lower and lower, fighting against the app trying to scroll back up since it's reached the end of the screen, you see more and more details underground.
Similarly, on the Citymapper Pass screen, if you keep scrolling for a long time you see a joke pass tier.
When viewing directions involving the London Underground, you're told which section of the train is best to be closest to the exit when you arrive. Instead of just using text, they use a picture of the train with a person hanging out of the window.
If you lose internet connectivity, as you're likely to if you're under ground, this bar pops up at the bottom of the app, and you can tap the map icon to see the London Underground map, so you've got options if you're lost.
When viewing the map on the home screen, the map colours are vibrant. I'd guess they're Citymapper's brand colours. But when viewing the map during trip planning, the colours become more muted so you can focus on landmarks more easily.
Citymapper have created illustrations for each city they support in the app.
If your app is set to a certain city, and Citymapper can see that you're in another city, it'll pop up this message on the home screen to make it easy for you to switch to the city you're in.
At the bottom of the settings page, the "mascot" of the city you've chosen is the one shown in front, with the other mascots in the background.
If you don't have notifications turned on, there's an unhappy person at the bottom of the screen. Once you turn them on, they're happy again.
The screen which shows the status of the Victoria line uses the Victoria line blue as its background colour. This is true of all of the status pages.
Citymapper integrates with lots of third party apps that let you book/find transport. Each of the pages dedicated to those third party apps colours the download button with that app's brand colour.
You're told how much you'll spend on a certain trip. If you choose to walk, which is free, instead you're told how many calories you'll burn, and how many of a random type of food that is equal to.