"Arknights" is a tower defense type of level-based mobile game. The playable characters in the game are called "agents", and players need to place the agents in the fixed battlefield to kill the enemies that enter the battlefield.

The agents are classified by rarity from 1-star to 6-star. According to different job positions， they are divided into eight major job categories and several sub-categories under each major category. Each job sub-category has different placement restrictions， placement costs， attack methods， attack range， attack damage type or trigger effects， etc. Each agent has talents that can affect its own characteristics or battlefield characteristics. Players can use items to upgrade or advance the agent itself and its skills， and can also strengthen the agent's talents and values to a certain extent through the "modular" system.

Players can obtain agents in two ways： by drawing cards through a system called "exploration"， or by spending items and time through "public recruitment" to obtain agents. In addition， there are agents obtained through event rewards. The drawing card system has a guarantee mechanism. After repeating the draw a certain number of times， a 6-star agent can be guaranteed to be obtained. When obtaining agents repeatedly， the attributes or talents of the agent can be slightly improved.

Players can carry up to 12 of their own agents and 1 "auxiliary" agent from a game friend to play general levels. Playing requires consuming player's energy (called "sensory")， which slowly recovers over time. When playing a level， each agent has different placement costs， health points and skill values： the placed points recovered over time are sufficient for the agent to be placed after the placement cost is met； when the health points reach zero， the agent will be forcibly removed from the battlefield and needs to wait for a period of time before being placed again； when the skill value is full， the agent can release skills to damage enemy units or heal friendly units， etc. When there are no enemies entering the "protected target" area， the player will receive a three-star evaluation. Each time a level is played， there is a probability of obtaining some cultivation materials to strengthen the agent， and when the first three-star evaluation is achieved， advanced currency can be obtained， which can be used to draw cards to obtain agents or purchase agent appearances， etc. After obtaining a three-star evaluation and not using the agent of a friend， players can consume the same or up to 6 times the energy in the future， and the system will automatically play the game according to the player's operation， but the battle process cannot be skipped.

In addition to general game levels， the game also has other gameplay systems： the "construction" system can perform operations for the cultivation of auxiliary agents， such as obtaining agent cultivation materials， advancing agent skills， etc.； the "integration strategy" system is a single-player linear node mode based on Roguelike， where players explore the linear nodes of the map through tower defense battles， construct the lineup and obtain bonus items； the "growth calculation" system is a single-player networked node mode based on base construction exploration， where players conduct tower defense battles and collect resources to build and upgrade the main base.