This requires an XBox controller (or a controller with XBox layout compatibility)

With your controller plugged in or connected, select the Controller icon in your steam library.
Select the controller layout under currently selected layout.
Under the community layouts tab for controller settings select "Best Settings"
Apply Layout
Start Game

"Best Settings" layout changes:
Left Trigger is Turbo Fire (best for Handgun/Machine Gun)
Right Trigger is Normal fire (best for Flamethrower as it won't cancel animation and seems to reach farther)
A is Turbo Jump
X is Power Slam
B is Normal Jump
Y is Normal Middle Mouse Function (this also operates to jump down a level from a catwalk platform)
Right Stick Button is screen shot

To Power Slam
This only works if you aren't using your left joystick (so you can't be moving around with the Left Stick for this macro to work)
While still... Hold Fire (LT or RT) + A then continuously press X

X is macro'd to Left Stick Down + Y which is the middle mouse multi function
Do not use Power Slam repeatedly over the water section (It will save the state from when you died at the point you're falling so re-spawning results in a death loop until you run out of lives.)

This also means that you can Power Slam on your own without X WHILE moving by using traditional jump (B) and running around holding Left Stick Down then pushing (Y). This is also fun but was annoying because without Best Settings you would have to reach to the Y from A to power slam.

This makes the game wicked easy, but also results in much less strain.
You might also discover the super jump glitch while using Power Slam.