That project has been made in 3 days less than 20 hours.
First of all, according to my benchmark tests, that project:
Works well at average of 60 fps with 140 agents on Samsung Galaxy Edge 7 which is $350 priced mid-level device.
Works well at average of 58-60 fps with 50 agents on Samsung Galaxy J7 Prime which is ~$170 priced low-level device.
and also It has,
Perfectly optimized Health Bar UI's on top of enemies , used UI Overlay, not world space canvas. This why perfectly optimized.
Perfectly optimized Object Pooling system to manage arrow projectiles, enemy spawns and any kind of Game Objects that will add in the future.
Fully customizable and editable in custom inspector panel AI's for Enemies and Base building.
Fully modular enemy and base controller scripts that has built on top of Attacker, Motor, UI, Animation, Target Searcher sub scripts.
Character and base datas stored in Scriptable Objects based on OOP, Polymorphism principles.
Fully customizable and easy to use 1 single API calls Audio Management system.
Super powerful leightweight and easy to use arrow projectile physics.