TheTunnels has just been released. There are plans to update the game regularly. There should be 4 minor updates per month and 1 major update per month. The game currently only has the main mining mode. A Tower Defense mode will be added in future updates.
Game release
Source: Steam Community (opens in a new tab)
Build and release context
Recorded Steam release date:
Within one calendar day of this post (UTC). The listed date does not establish an exact launch time.