To thoroughly enjoy this game you either need to be a child or maintain a sense of childlike discovery. There is no objective, no score, no gameover, no win conditions, no time limits. This isn't even really a game. Cosmic Osmo is a discovery experience that appeals to the humorous light hearted surreal nature of kids and those of us lucky enough to still be kids at heart.
It plays much like a point and click adventure game, but without inventory or really plotline, your only driving motivation is to see what you can find next. You are essentially an alien visitor to a very strange and exotic solar system, the home of the titular Cosmic Osmo. You can use a spacecraft to navigate between multiple planets or use a very complex series of tunnels, teleporters, and other surreal means of navigation to traverse around this highly entertaining landscape.
While the game certainly looks dated, the black and white cartoony style still maintains a lot of charm and is just as enjoyable today as it was in the early 90s when it was first released. A really fun game to play with your kids or by yourself, you'll be amazed that despite it's age this game contains a huge wealth of interesting and entertaining things to explore, ensuring that you'll discover something new each time you play.