im new to speedruning and i wood like to start here and i tip

Before speedrunning, play every level so you have a basic understanding of the location where you spawn, and where the boss spawns. Always use the best weapon available, scroll your mouse wheel to see if you have any other weapons in the level. Also try to use a grenade before shooting the boss.

Like in other FPS games, you deal more damage if you do headshots. Also the best weapon is shotgun, you will get it after beating Week 2.