The interface is very intuitive. From the drop-down menu to the left you can quickly access a list of all the available series, ordered alphabetically or by popularity. You can also see a list of the episodes you downloaded, and take a look at the latest animated movies.
One of the strong points of Toonmania is the ability to choose how you want to watch the episodes, either streaming them or downloading them to your device. You can also send them directly to your Chromecast device if you have one.
Toonmania is an excellent app for watching animated series like Adventure Time, Gravity Falls, and others. It lets you enjoy all the episodes easily, and offers a lot of different possibilities in which to do it.