If you make it to (1) fast enough (with saw boosts or shotgun boosts and bunny hopping) you can skip both buttons (2) and (3), completing the level under 13 seconds.



After pressing the button (1) go through the wall. Saves you fighting 2 jetpack guys, one button press and going down at elevator speed.



If you have enough health, you can go under the second elevator, drop into lava and swim to your right, until you reach the exit of the lava room. It's possible to get on a platform and save even more time, although I weren't able to do this. You need to trigger the last platform over the lava to fall, in order for the gate to open.

Here's a gif on giphy[giphy.com]

Just granade jump out of the arena instead of fighting it.




Plenty of granade jumps possible here.

In order to skip the second building granade jump (with a help of a shotty boost) up, go through a hole in the wall and then granade jup right to the top.



To skip the arena with ninjas (or swordguys), granade jump after the police car. It takes two granade jumps to take you to the top of the level. You can hug the wall while attacking it with a saw to avoid fall damage (pictured as green arrow).




After pressing the button (1) go up and straight to the exit before the wall cuts you off.




Kill the worker with your railgun as pictured by the red arrow, so he can't open the roof doors. You don't have to fight the police cars.



Granade jump straight to the final arena skipping a buch of elevators and enemies.