You can earn experience points by completing your room design tasks and merging high-level items.
Experience points are mergeable, and you can earn more if you merge and collect them from your board.
Once you collect enough experience points, you level up.
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You can always check your experience points from the upper-left corner of your game board.
Please click the bar that shows your level to see how many experience points you need to level up.
Learn more about Mergedom: Home Design merge puzzle game.