Oscar the Balloonist Dives into the Lake follows the further adventures of
the young hero of Oscar the Balloonist and the Secrets of the Forest as he
heads to the lake to visit Balthasar Pumpernickel, an animal researcher.
Balthasar is afraid of the animals he’s supposed to be studying, so he’s
relieved when Oscar agrees to help him out.

Gameplay and hand-painted appearance is similar to other Tivola games
developed by BVM, such as the previous Oscar the Balloonist title and Millie
Meter and Her Adventures in the Oak Tree. Actions are performed with the
mouse, and clicking on items activates animations. There is a row of icons at
the bottom of the screen for accessing games, returning to the lake, changing
seasons, changing language, and exiting.

Oscar’s balloon is divided into four quadrants, one for each season – clicking
on one of the tree pictures will bring up that season on the lake, and the
animals around it will explain how they live at that time of the year. There
are 12 mini-games, five of which are available to play from the start – the
other seven are hidden in the game and only become accessible as the player
uncovers them.