After installing Unity for Linux (v5.3.5f1 Personal on linux mint 17.3 cinnamon, using x64 deb package), I was able to create a new project without problems, but I had issues with reopening that same project. The second time I tried to open it, the launcher closed, and an empty “Hang on” window appeared. After a while (10-20 minutes) I eventually terminated Unity and restarted. This time, it had problems with the lock file (in the Temp directory of my project). I deleted that lock file, and the editor launched just fine. The same pattern repeats 90% of the times I try to open a project.
Also, note that after the editor launches, an error appears on the console: “Socket bind failed, error: Address already in use (98)”, that does not seem to affect anything though.
On top of that, the splash screen (“Starting Unity…”) does not disappear, until the editor starts.