The 3D-puzzle game cocoon let you play a small insect in a futuristic-insectoid world solving puzzles and surviving boss fights along its journey. You start on a desert-rock planet and activate switches to move forward. Soon after this simple start you learn that this desert world is contained in a small orange sphere you can exit and reenter at certain stations. Throughout the game you will find three more of these spheres and each of them containing its own world, for example the green sphere with a green swamp land in it or the purple sphere bringing you to a dark cave area. The clue is that after leaving a sphere you can carry it and enter other spheres with it. For example, you can take the orange sphere containing the desert world into the green swamp land allowing you to pass over bridges, which can only be activated if you carry the orange sphere with you.

Like activating those bridges using the orange spheres all the spheres come with a unique capability. The green sphere for example allows you to change small pillars from concrete form to gas form and vice versa allowing you to reach higher up platforms. The game does a great job of designing puzzles using the combination of the spheres capabilities and changing between the worlds and combining them into another. Latest after you are in possession of all the spheres some of the puzzles are quite challenging forcing you to really think about how to combine certain spheres into another and how a certain action inside on sphere might impact the world inside another. In each of the worlds there is an additional puzzle to be solved which will make a small drone being your companion and eliminating barriers for you. This allows you to proceed further into new areas and make returning into the early worlds interesting as you will find new puzzles to solve.

Even though you change quite often between all worlds and spheres the game is fully linear. On some occasions you can find so called moon ancestors a bit off the main path which are the only optional collectibles in the game.

A true highlight are the boss fights in which you fight larger insectoid enemies. They add a certain dynamic and usually have multiple phases. Mostly the clue is to understand their movement pattern, avoid their attacks and counterattack yourself using a certain mechanism specific to each boss. The boss encounters are not overly hard but need some attempts to understand movement patterns and the way to beat them. In addition, their variety in design and attacks is excellent, ranging from simple attacks like rushing upon you to area damage attacks and even a bit of bullet hell action.