[EDIT: On up-to-date versions of the game and Steam, this should no longer be a problem]
Hey! We just learned that there was an update to the Steam Beta client on the 18th that is causing Crashlands to be unable to boot. If you can't boot your game, just do the following steps:
1. Go to the "Steam" menu in the top left.
2. Go to "Settings"
3. Under the "Account" tab, look for the "Beta Participation" section.
4. Set your beta participation to be "None - Opt out".
Then, Steam will restart and Crashlands will launch without a hitch!