I think it's manipulation of the game's RAM, I think that's why they use Cheat Engine, there must be a block in memory where enemies will appear per room is stored, and another block of memory where they will have HP.

in the WOLFDNC video it appears, it shows the enemies and the life of each one-

Hello, I want to practice for some speedruns, is there a program to see the total enemies in a room? to see the life of each one?

Thank you very much.