This page does not have an official English name. However, all pages will use Research Institute to refer to it.
Research Institute (研究所; pinyin: Yánjiū Suǒ; lit. translation: Research Institute) is the third world in the Chinese version of Plants vs. Zombies 3 introduced in the second beta test of the game as part of the World Adventure game mode. This world offers a total of 20 levels to play (10 on Normal Mode, 10 on Hard Mode), 5 plants to acquire, 6 evolutions to discover, and 9 zombies to fight against.
This world has three mechanisms, Electromagnetic Emitters[?] (電磁發射裝置; pinyin: Diàncí Fāshè Zhuāngzhì), Mechanical Tombstones[?] (機械墓碑; pinyin: Jīxiè Mùbēi), and Drones[?] (無人機; pinyin: Wúrén Jī):
Electromagnetic Emitters: Some columns of the lawn will have a device above the topmost lane that emit an electromagnetic zap every once in a while, which deals a small amount of damage and paralyzes for a short period of time any plants within the device's column. If an electric attribute plants gets zapped by the device, nothing will happen to it, making electric attribute plants a counter to this mechanism. (Exclusive from the third beta test and onwards)
Mechanical Tombstones: Occassionally an amount of mechanical tombstones will be dropped on the lawn on random tiles, which said tombstones have a timer set on them, and a specific zombie will be spawned upon the time out of the specific tombstone, after which the timer will reset and repeat this until the tombstone itself is destroyed. They come in three variations: 1. Spawns an Institute Zombie every 20 seconds, has low health; 2. Spawns an Institute Conehead every 40 seconds, has medium health; 3. Spawns a Secret Services Zombie every 60 seconds, has high health. These tombstones also act like zombies, meaning that lobber plants will not ignore them to prioritize other zombies in the lane, and they can have effects applied to them such as Convallaria Pharmacist's poison. They can additionally be stunned for a very few seconds by certain electric attacks.
Drones: Some columns of the lawn will have a landing pad with a drone above the topmost lane that will fly over its column to do a check-up on whether the column contains any plants or not. Upon detecting the first plant on its way, it will alert a Secret Services Zombie that will drop down from above on the tile of the detected plant, after which the drone will go back to its landing pad without going further down the column. In case there is no plants in the column, the drone will simply go back to its landing pad without alerting any Secret Services Zombies to come down.
Prior to the third beta test of the game, some levels would be set at a night-time setting, which would stop the falling of sun from the sky for the entire level.
Contents of levels 5, 6, 7, 8, 9 and 10 of this world are unknown for the time being, due to level 4 of this world being physically impossible to clear, as the level provided no seed packets, even if the player had chosen their plants. It is unknown as to whether this was intentional, an oversight, a time constraint, or a possible bug/glitch for the time being.
Note: Majority of non-branch levels can optionally pre-select 7 or 8 random plants that can be unselected or no optionally pre-selected plants at all, with different type of pre-selection for each player. If a level has one or more locked pre-selections, the level can optionally pre-selected 7 or less random plants instead, with different type of pre-selection for each player again.
Re-balanced Mechanical Tombstones mechanism: 1. 20-seconds timed tombstones will now spawn Institute Zombies instead of Institute Coneheads, and the health of the tombstones has been lowered; 2. 40-seconds timed tombstones will now spawn Institute Coneheads instead of Experimenter Zombies, and the health of the tombstones has been lowered; 3. The health of the 60-seconds timed tombstones has been lowered.
The number of levels in the world has been changed and a Hard Mode has been added, changing the number of levels from 16 levels to 20 levels (10 on Normal Mode and 10 on Hard Mode), which said new levels differ in level design from the second beta's levels, as well as removing the Grave Danger and the Duel level paths (levels 4-1, 4-2, 12-1, 12-2 and 8-1, 8-2, 15-1, 15-2 respectively).
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