Ironworks Facility

• stage 1 If you make it through the level fast enough and get to the arena where there is a tunnel at the bottom left and lava at the bottom, you can skip the fight and buttons by going through a secret tunnel. The opening closes quickly so use shotgun boost, b-hooping and saw boost to get there on time.

• stage 4 During the second combat/arena after pressing the button that is positioned on the right of the arena you are able to go through the wall and drop down, this skip saves from fighting two jetpack guys and the elevator falling 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 might be possible to get on a platform and save even more time although remeber you will need to trigger the last platform over the lava to fall, in order for the gate to open.

(the rest is yet to be edited/annotated/added to) Volcano research station -Stage 1 Just grenade jump out of the arena instead of fighting it.

Stage 4 Plenty of grenade jumps possible here.

Last City stage 1 In order to skip the second building grenade jump (with a help of a shotty boost) up, go through a hole in the wall and then grenade up right to the top.

To skip the arena with ninjas (or sword guys), grenade jump after the police car. It takes two grenade 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). stage 2

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

stage 4 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.

Grenade jump straight to the final arena skipping a bunch of elevators and enemies.

information comes from Barnaba and myself