Yes. While creating Expedition, we realized that our players might not always have a phone on them, but we decided to make the app required for two reasons:
1 - using an app enables us to do really cool things, like realtime combat and in-app quests. Plus, because it's free to send out app updates, we can continue to add new and exciting game modes and mechanics even after you've received your deck!
2 - only supporting play via the app saves us a lot of time and money in manufacturing and shipping additional components, making the game cheaper for you and allowing us to innovate at a faster pace.
To make it as easy as possible to use the app, we've made it available in two forms. First, as a web app available at app.expeditiongame.com - no installation required, and it works on all mobile operating systems. Secondly, as an Android and iOS app so that you can play without needing an internet connection.