RetroWar is no longer 'in beta', it is full 'early access' released. However we still want to add new features for you to test, and so there is now BETA branch you can opt-in.
You will need to right-click on RetroWar in your Steam library, select properties, betas, change none->beta.
Players have requested achievements, and so achievements have now been added in the beta branch. Can you think of any more ideas for achievements?