Levels in MilMo are gained via Experience, or XP. There are currently 21 levels in the game, each with increasing benefits such as more Hearts, Abilities, and access to new Areas. As the player's level increases, they are able to defeat higher-levelled Monsters such as Hunting Dinos, whilst lower-level monsters such as Sand Crabs will give out little to no XP. Having a low level makes it difficult to defeat higher-levelled Monsters, even with a Weapon with high stats.
At levels 5, 10, 15, and 21, players are asked to choose a Class Direction. This ends with the player receiving a Class Ability, whilst at levels 4, 7, 11, 14, 18, and 21, the player receives half a heart, which gives them higher Health Points.