Game Log File
Windows
Steam Version: c:\Program Files (x86)\Steam\SteamApps\common\Particle Fleet Emergence\ParticleFleet_Data\output_log.txt
Non-Steam Version: c:\Users\YOUR_USER\AppData\Roaming\ParticleFleet\log.txt
OS X
~/Library/Logs/Unity/Player.log
Note: Make sure the directory is not hidden: http://osxdaily.com/2011/07/04/show-library-directory-in-mac-os-x-lion/
Linux/SteamOS
~/.config/unity3d/Knuckle Cracker/Particle Fleet/Player.log
Game Save Directory
Windows
c:\Users\YOUR_USER\Documents\My Games\particlefleet
OS X
~/Library/Application Support/com.knucklecracker/particlefleet
Linux/SteamOS
~/.local/share/knucklecracker/particlefleet