Very strange! Can you please try validating the steam cache for the game?

Please submit a player.log as instructed here:

How to: Submit a Bug Ticket

Hi Sam. It appears that you have accidentally linked the player log of a different Unity-based game. Could you please upload one for War for the Overworld after receiving the level 7 crash?

Cheers.

Thanks for the report. Unfortunately there isn't any immediate action we can take, however we will continue to monitor for further reports to determine the root cause.