Hi Guys,
First I want to extend my sincere apologies to anyone who has been frustrated trying to run the game. I will endeavour to properly patch this in the future, but for now there is a workaround:
Navigate to Steam\steamapps\common\Reveal The Deep\
Right click "rtd.jar" and select "Open with" > Java(TM) Platform SE Binary.
The game should now run as intended.
I appreciate this isn't an adequate solution and I'm working on a patch to stop WinRAR interfering with the game running.