Same here, game does not launch on ubuntu 18.04 or any version of Proton.

Using a GTX 1070 and Ryzen 1700.

Same behaviour on my machine, Ubuntu 18.04, Intel X5460, Nvidia GTX 1060 3GB with 396.54 driver.

Looking at the log;

wine: Call from 0x7b43c45c to unimplemented function mscoree.dll.CorIsLatestSvc, aborting

with other words, this game requires .NET, which Proton does not have. See bug #18.

Log: steam-255070.log

After downloading the game on Steam, but before launching it, navigate to the game's redist folder (.../steamapps/common/abyss_odyssey/_CommonRedist/) and delete the DotNet and vcredist folders. Once that is done, click the play button; the game won't launch, but it will generate the game's prefix (.../steamapps/compatdata/255070/pfx/). Install xact and xna40 to this prefix via winetricks/protontricks, and the game should be able to launch properly.

Install xact xna40 dotnet452 & vcruntime2010, in that order, the game then runs with no issues (for me).