The program is downloadable under: https://github.com/thesquarefox/hamsterbeer/raw/main/HamstersDenTavern.zip.

Just unzip it and run 'HamstersDenTavern.exe'.
(You may need to install DirectX 9 and Visual Studio 2019 redistributable.)

It looks then like this:

Now click on the button "Drink the Beer!".

After you drank the beer, it looks like this:

The achievement should now be unlocked.

Steam has to be running in the background and you need to own Aquanox: Deep Descent, otherwise the tavern simulator will hangup, since you cannot get the achievement from Steam side.

Skal!
Squarefox, the Hamster friend.