Critical Studio and Paradox Interactive have tweaked the action-RPG Dungeonland to support a free-to-play model, opening access to portions of the game. The DM Tower stage is now unlocked for regular play and the DM Mode in which one player tries to screw over everyone else.
This is one of those games that lives and dies based on who's playing, so I can absolutely see why they'd want to lower the barrier to entry here.
To get the remaining content that's now locked out, there's an all-access pass -- it normally goes for $9.99 but is currently on sale for $4.99. As expected, if you previously owned the game, you're automatically upgraded to all-access. That also extends to existing gift copies of Dungeonland.