Thanks for letting me know about the bug, the logs should be stored in one of the following locations. If you could email it to me at david@alvariusgames.com it would be appreciated.
Windows: %APPDATA%\Godot\app_userdata\bearcycle
macOS: ~/Library/Application Support/Godot/app_userdata/bearcycle
Linux: ~/.local/share/godot/app_userdata/bearcycle
Glad you think the rocket booster can be precise! Its sort of like the Rocket League booster, feathering does help a bit.