Hello!
I have the same issue! Downloaded the game yesterday from itch.io Spacemen-1129-linux-x86.
I run the game using Ubuntu 16.04 on a Mate environment. ASUS Zenbook. Wenn starting the game, I got the stars background, several spacemen processes turn CPU to 100% and memory usage jumps from around 2 GB to 4,7 GB. First I thought it's while universe is generated, but I waited for a while and it don't stop.
Run the game in a terminal I got some warnings. First there is a "Bad compile of:" with an sourcecode excerpt of 413 lines of code. Then a lot of
WARNUNG: Style: nifty-chat-control#chatTextArea was already registered. The new definition will override the previous.
Jul 29, 2017 9:53:40 AM de.lessvoid.nifty.Nifty registerStyle
It ends up with a message resumed every few seconds:
Jul 29, 2017 9:59:33 AM com.jme3.bullet.PhysicsSpace removeRigidBody
WARNUNG: RigidBody ro.fbucur.spacemen.controls.ShipControl@2016f0fb does not exist in PhysicsSpace, cannot remove.
greetings, nunatak