Go to the end of the first level and, instead of going through the exit, turn right and open a secret door in the corner of the wall. Then, turn 90 degrees to your right to open another secret passage. At the end, you will find the elevator to level 10.
Start the game with the "-goobers" command line parameter. Press LEFT SHIFT + ALT + BACKSPACE to enable debug mode. Activate the following cheats by entering the corresponding codes:
CHEAT FUNCTION - CHEAT CODE Change border color - TAB + B Display number of items, doors, and actors - TAB + C Skip two levels - TAB + E Displays coordinates - TAB + F Toggle God mode - TAB + G Lose health - TAB + H Free items - TAB + I Display memory usage - TAB + M Pause without message - TAB + P Exit game - TAB + Q Toggle slow motion - TAB + S View graphics and play sounds - TAB + T Add extra VBLs - TAB + V Level select - TAB + W Extra stuff - TAB + X
Start the game with the -tedlevel < level numnber >command line parameter. The level number is a two digit number with the tens digit representing the episode minus one and the ones digit representing the level number minus one.
Press L + I + M during game play. Note: Your score will reset to zero after this cheat is enabled.
Note: Each time this code is used, ten minutes gets added to your level completion time. If you are one to get below par, do not use this code to get the keys you need; you are better off going through the level.