Maze

Maze is a unique temporary game mode that works similarly to Free For All, replacing the now-removed Mothership mode. However, there are massive gray walls that are scattered around the arena, giving the arena the appearance of a maze. These walls are impenetrable by Tanks or their bullets/Traps. The minimap displays these walls accordingly, allowing you to find your way around.

The scoreboard and leveling system is exactly like FFA. The goal of this mode also remains the same: be the player at the top of the Scoreboard, and avoid dying for as long as you can. The massive walls make survival significantly more difficult, as the player is easily able to be backed into a corner with no escape.

Unlike other game modes, bosses do not spawn in Maze.

Strategy

First of all, use the minimap to your advantage. Hide behind walls if need be, using them to protect you from heavy fire. Often there are cases where small "rooms" can be filled with a load of untouched polygons, so it would be in your best interest to search out for one of these. Otherwise, beware: it is incredibly easy to be backed into a wall by multiple enemies, and readily slaughtered, even at the highest levels - the fact that bosses do not spawn comes as a mixed blessing due to this fact. The most effective strategy in this mode is to use a build that allows you to easily corner other players. The classes that are the most effective are generally ramming builds and tanks inside the summoning class. Classes that spam bullets with heavy damage are effective, although the barriers may block your bullets. Such classes include Octotanks or the Triple Twin.

Use the walls to your advantage if you are a Trapper class. Find a corner and build a wall of mines around it, creating a semi-permanent fort. However, this only works well if you can properly defend yourself, either as an Auto Trapper or Gunner Trapper. It is an overall risky strategy, since if multiple enemies come bearing down on you, you have no escape route but straight into the enemy.

Manager is very good in this mode too, as you can become invisible and control drones. It states above that drone-user classes are effective in Maze mode. Becoming invisible is another positive aspect making it impossible for anyone to see you when invisible.

Also, once you are leveled up, pay attention to your mini-map. There is often at least one area of the map the will have a variable-size room with 1 entrance. The less entrances and the more reasonable size it is, the better. Make sure to sweep any hostiles out of the area first. If a 1-entrance chamber cannot be found, go for something close (see mini-map above for reference).

As this is also the game mode with the most/largest teams, ensure you have protocols to use against them. Crowd control tanks work well.

History

This game mode was added on September 22nd, 2016.
Before September 23rd, crashers couldn't go through walls.
On September 23rd, the walls were made "less sticky", which may have fixed some bugs.
As of before, the Arena Closers could not go through the walls, which made it possible to survive their onslaught, at least until the server forcefully closed. Like the crashers, they can now go through walls.
Since 25th September, 2016, the wall kills the drones.

Trivia

A battle in Maze lasts for no longer than 5 hours before being closed.
This is the first gamemode with any sort of complete physical barrier, other than the outside border.
- The barriers also appear to resemble the edges of the Base in 2 Teams and 4 Teams, as they give knockback, except without Body Damage.
There is a glitch with this gamemode where most entities will disappear and the game will become unplayable.
- On September 23rd, the walls were made "less sticky", which may have fixed some of these issues.
Maze was switched with Sandbox, in that you must disable adblock (and any tracking protection) before you are allowed to play. Also, any "tracking protection" in some browsers, like Firefox, had to be disabled as well.
This now makes Maze the only game mode - in fact, the only feature in all of Diep.io - to be purposefully disabled for certain users.

A maze button when using adblock.

The leader arrow is not visible behind walls.
There was a glitch that let the drones of the Overseer and Manager (not verified if the Necromancer’s drones could do this) freely go through walls.
- However since 25th September, 2016, the wall kills the drones. So even if the drones succeed to go through the wall, the wall will kill them.
There is a low chance of a Pentagon to spawn inside the walls in the Pentagon Nest.
As this Game Mode was released, something was changed in the properties of invisible map borders in the whole game, they now shake your tank if you try to move out of the map.
There used to be a glitch. Sometimes if you moved to the corner of two walls, you would stick to the wall and become permanently immobilized.
Maze tends to be the the toughest game mode in terms of survival, newly joined players might find it very hard to avoid merciless deaths from higher level tanks. Teaming in the Maze became a common phenomenon as well. This has died down considerably.
The walls are randomly generated.
- Sometimes because of this, a huge chunk of maze wall will take up the middle of the map, disabling most of the playable area and the Pentagon nest.