MASS Builder is a game where gamers pilot a customizable MASS (Mechanical Assault Skeleton Suit) as they attempt to contain the threat of quarks. The plot premise encourages immediate immersion, and the game world is rich in information. The gameplay focuses on the dynamics of battles against massive squads of enemies.

In MASS Builder, the debut stage is a tutorial and introduces gamers to the gameplay features. However, some game elements are not displayed here, especially those aimed at battle. There are elements of not only a role-playing game, but also actions that balance each other, but the shortcomings of the textbook are leveled out by the reference book, where you can familiarize yourself with all the intricacies of the game.

The game also provides a world map, which does not play any important role other than showing the points where you need to advance during missions. The latter are divided into side and plot ones that move the plot forward. The game also allows you to purchase more resources and credits to improve your technology for upcoming missions, especially those related to story development.

The gameplay offers fast-paced combat, but it becomes monotonous, especially after the first few stages. This is due to the apparent lack of a combo system, unless you take into account the fact that you can ram enemies using the abilities supplied by super technology. However, the customization changes the weapon's behavior, offering some variation in combat and the illusion of a well-designed combat system.

The strongest advantage here is the customization, which has 2 types of equipment: performance and pure aesthetics equipment. The first is visible in the weapons section and changes the weapon's behavior and suit performance, which is useful for combating more powerful quarks. The second is in the armor section, where the player can customize the entire unit from head to toe.