The Mode is voted on by the players during the first sixty seconds of the game. There are eight Modes and four Modifiers to choose from. The player must also select their Rank Set at this time.
Depending on the Mode chosen, a great deal of gameplay elements are affected. These elements include but are not limited to the number of enemies that spawn, the types of enemies that spawn, the stats of the enemies that spawn, the difficulty of mission objectives, the Medals and Unlockables that a player can qualify for, the Skill Identifiers that are eligible to be unlocked, and more.
The Modifiers are somewhat more straightforward. Each Modifier adds a single persistent element or restriction to the gameplay of that one game and more than one Modifier can be chosen. These Modifiers also change the Medals and Unlockables that a player can qualify for.
|Recruit||This Mode features standard missions and offers the easiest game possible. This mode is recommended for new players to learn the game with. Experience rewards are low, but enemies are easy to defeat and pose very little threat with their reduced move speed and damage.|
|Normal||This Mode features standard missions and offers an acceptable difficulty of gameplay for public games. Enemies are no longer pushovers as they were in Recruit, and the experience for completing objectives is reasonable with regard to difficulty. Even experienced teams will need teamwork to optimally complete this mode.|
|Hard||This Mode features standard missions and offers a reasonable challenge for public games. Enemies have bolstered their health and will not fall easily. Increased movement speed and damage means even basic enemies are a threat. Bosses will not fall easily with their greatly increased health pools. With sufficiently skilled players, the increased experience gain in this Mode makes it worthwhile.|
|Insane||This Mode features standard missions and offers a true challenge for hardcore players and should only be attempted by partied groups, preferably in private lobbies. Division of labor and deliberate selection of MOS by players is crucial to success, and a thorough understanding of one role while integrating teamwork is the only way to successfully complete this Mode. While the experience gain is very high, the difficulty of completing them in the midst of such a challenging Mode means failed missions may so frequent as to negate the experience bonus from this Mode.|
|Nightmare||This Mode features standard missions and offers the ultimate challenge for the most veteran of players in Undead Assault 3. Any group of players attempting this Mode without clear and prior communication of roles, expectations, strategies, and plans in a private lobby with highly experienced players will be wasting their time. Various members of the group should be expected to have end-game unlocks, such as the [VT] Skill Identifier, in order to fulfill roles otherwise impossible for low-Rank players. The experience gain for completing objectives in this mode is second to none, but that is assuming your team can complete more objectives than it fails.|
|Competitive||This Mode features a varied set of competitive missions for a player-versus-player style battle royale where each player must fight to win on a round-by-round basis. Rounds will cycle through different mission objectives for either individual players or teams of players, and the player with the most rounds won at the end of the Mode is declared the winner. Modifiers cannot be used with this Mode. The experience rewards are relatively high compared to other Modes.|
|Survival||This Mode features a survival mission for any number of players willing to spend up to 50 minutes evading the enemy horde while dwindling it enough to keep the Infestation Level under control. Various difficult bosses will spawn at designated time intervals, and an Infestation Level of above 40 will cause zombies to spawn with Mutations, making the task that much harder. After 15 minutes, experience gain happens in intervals of 5 minutes. Victory is attained after 50 minutes if at least one player is still alive. This Mode is viable for games with low player count, as it is possible to complete with as few as 1-2 players.|
|PMC||This Mode features PMC missions and offers a unique challenge completely different from all other modes. The players face off against an opposing force of Private Military Contractors with similar offensive capabilities in the way of ranged weapons, explosives, and indirect fire support. The missions in this Mode follow its own storyline rather than along the standard missions, and a great deal of strategizing and effort is required to successfully subdue these capable PMCs in order to complete this Mode.|
|Outbreak||Mostly masses of Tier 3 zombies spawn. Tier 3 zombies have 6% more health and 15% more damage. Cannot be selected together with Tier 1. Increases XP gain by 10%.|
|Rifle||Players can only choose either the Rifleman or the Combat Medic MOS. Increases XP gain by 25%.|
|Tier 1||Mostly Tier 1 zombies spawn. Cannot be selected together with Outbreak. Increases XP gain by 10%.|
|1 Life||Combat Medics' Revive ability is replaced with Marksmanship ability. No revives or reinforcements upon death. Requires at least 3 players. Increases XP gain by 15%.|