Tunnel of Doom is now available for Steam users in China, and has been updated with Chinese language support.
The game is also going to be in Steam's 'Going Rogue: Festival of Persistence' event, which starts 2 May (10am PT) and ends 9 May (10am PT). The Tunnel of Doom demo will be free to download for the duration of the event, and the full game will be available with a 20% discount.
https://store.steampowered.com/app/1361840/Tunnel_of_Doom/