Hint for AO boardroom level
 

In the board room level where the time is running out, go down to the second screen after coming out of the door and watching the movie. Run up and jump into the shadowy area where the timer is and roll down. You should land where the lever is. This saves alot of time. I will try and get a screen shot later.

Yep, this is the final ultimate secret in Abe's Oddysee. However, if you're not going for the perfect ending (by rescuing all 99 Muds), you can save a bit more time and frustration by ignoring that last scrub and dropping directly down into the board room. As long as you pull that lever, you'll end the game regardless of whether you get killed.

Yep. Max the mug's right. Pull that lever, you get 2 sets of sligs on ya. 2 shoot ya, 2 whack ya. You finish the game.