Merge Merge: Brainrot Drop is a Suika merge game similar to Merge Fellas. The player attempts to earn coins and a high score by merging objects in a glass container in a room. Their overall objective is to create one ultimate evolution.
The game features nine themes and six backgrounds. It provides a Theme tab in the lower-right area that the player can use to select one of each. That said, they only receive so many free ones. They must save enough coins to purchase some as well. The objects range from meme characters to anthropomorphic objects based on astronomy, food, holidays and sports.
No matter the theme, the player must merge two identical objects to create a new one. For example, they might merge two hamburgers or two specific planets. They then receive coins in the upper-left area. They can double their coins by watching advertisements. If they perform a streak, they also receive gift boxes that carry rewards. They can track their gift box progress on a bar under the upper-center score.
Merge Merge: Brainrot gives the player a preview of each new object in the upper-right corner. It doesn't provide an evolution arrow or guide, but it reveals the player's achievements by increasing the coin rewards.
The player also receives three boosters. To improve the amount of container space and the chance of a merge, they can remove all small objects, remove one object, or shake the container. After they use these tools once, they must watch videos to continue receiving access.