Increase Cash (Bug Exploitation):
 Just before completing the mission, do a save or quicksave. 
 Complete the mission and save it in a different save slot. 
 Reload your last save or quicksave before completing the 
 mission. Complete the mission again. 
 The statistics screen should now have ADDED TOGETHER the 
 loot from BOTH mission completions. Apparently, the variable 
 which stores treasure amount at the end of the mission is not 
 being cleared between loads. 
 You can keep doing this until you have all the cash you need 
 to buy out the store at the loadout screen for the mission 
 immediately following. 
 
 Level skip
 While playing a game, press [Ctrl] + [Alt] + [Shift] + [End].
 
 More money
 
 Save the game immediately before completing a mission. Complete the
 mission as usual, and save the game in a different save position.
 Reload save that was made before the mission was completed. Complete
 the mission again. The statistics screen will combine the money from
 both missions. Repeat this to earn as much as needed.
 
 Extra money
 
 Note: This procedure involves editing a game file; create a backup
 copy of the file before proceeding. Use a text editor to edit the
 "dark.cfg" file in the game directory. Change the value after the
 "cash_bonus" entry to increase the amount of additional money
 available at the start of each level. 
 
 
 Modify Starting Cash:
 You can edit the dark.cfg file and add the line 
 "cash_bonus n" N represents the amount of cash added 
 to the beginning of a mission. 
 
 
 Easy no kill missions:
 Note: This procedure involves editing a game file; create 
 a backup copy of the file before proceeding. Use a text 
 editor to edit the "user.cfg" file in the game directory. 
 Enter "cheats_active" on a new line, then enter 
 ""nokillgoalcheat" on the next line. You will now be 
 able to pass the objectives in any mission that requires 
 you not to kill anyone. 
 
 More money:
 Save the game immediately before completing a mission. 
 Complete the mission as usual, and save the game in a 
 different save position. Reload save that was made before 
 the mission was completed. Complete the mission again. 
 The statistics screen will combine the money from both 
 missions. Repeat this to earn as much as needed. 
 
 
 Almost all doors and chest unlocked:
 Note: This procedure involves editing a game file; create a 
 backup copy of the file before proceeding. Use a text editor 
 to edit the "user.cfg" file in the game directory. 
 Enter "cheats_active" on a new line, then enter "lockcheat" 
 on the next line. 
 
 Expert mode:
 Note: This procedure involves editing a game file; create a 
 backup copy of the file before proceeding. Use a text editor 
 to edit the "user.cfg" file in the game directory. 
 Enter "cheats_active" on a new line, the enter one or more 
 the following lines after it. 
 FailOnSee
 FailOnKO
 FailOnKill 
 
 Each mission will be easier to fail.