It is a bit ambiguous in this case.
We found unfinished non-core content:
Grendizer U: The Inception (Alternative Version)
Doronjo-sama wa Tensei shitemo Akuyaku Reijou no Mama Datta (Spin-Off)
Here you have all the anime relations we detected ordered by release date, so you can see the reason for this status in context and also use it as watching order.
The mangas and the non-core contents are excluded by default, but you can enable them by clicking the buttons below:
Anime - Base
Release date: July 13, 2013
Anime - Sequel
Release date: June 20, 2015
Anime - Sequel
Release date: July 05, 2015
Gatchaman Crowds follows the story of Hajime Ichinose, an energetic and somewhat eccentric young woman who is unexpectedly chosen to become a Gatchaman, a member of a secret team tasked with protecting the city from dangerous aliens known as MESS.
Hajime's induction into the Gatchaman world is abrupt, guided by the serious and dedicated Sugane Tachibana, who emphasizes the importance of secrecy.
Under the guidance of their alien leader, Paiman, the Gatchaman must learn to use their unique abilities and cooperate to combat the growing threat of the MESS, beings capable of causing widespread destruction.
As Hajime adjusts to her new role, she must navigate the complex dynamics of the team and find her own way to contribute to their mission of protecting humanity from this unseen enemy.