Disclaimer: Firstly, I would like to echo what caffeine said in the No rom requests! thread: Do not use this public forum to ask other people to assist you in something illegal. If you wish to use MAME and the cheats within this thread, the moral and legal responsibility is entirely your own. The cheat.dat and how to enable it: I'm going to assume that users of OS X and Linux are savvy enough to do this entirely for themselves, or at least adapt these instructions, so this is targetted at Windows users. Although it is possible to download pre-made cheat.dat files (from here for example), they usually contain lots of cheats for games you'll never play, so I would recommend creating your own file. The cheat.dat is just a plain text file, so you can create it with notepad or your favourite text editor; simply copy and paste new cheats in, and then save the file. The cheats can be pasted in anywhere within the file, although it makes sense to group cheats for the same game together. Also, make sure to keep the cheats to a one per line format. If you want to add comments to your cheat.dat, or comment out cheats, simply put a semi-colon ( at the start of the line. When saving, make sure whatever text editor you used does not append a ".txt" to the filename, if it does, you will need to rename it. The cheat.dat should be placed in the same directory as your MAME executable. (Note for MAME OS X users: I've been reliably informed by Rosti that the cheat.dat should be placed in ~/Library/Application Support/MAME OS X/ ) To enable cheats, find the file MAME.ini (which should also be in the same directory as your MAME executable), and open it up in your favourite text editor. Under "CORE MISC OPTIONS" change "cheat" from 0 to 1 (or off to on), and save the file. Note that most MAME front-ends or builds with a built-in GUI create MAME.ini automatically; if you're using a command line, and can't find the file, you may have to create it by running "mame -createconfig". Using Cheats: When you press the "Tab" key during play, a menu should pop up. If cheating has been properly enabled, you should see a "Cheat" submenu, and within that, an "Enable/Disable a Cheat" submenu. Most cheats will be switched on and off by using "left" and "right" keys; there might be a few cheats that say "Set", to enable these, highlight them and press "Enter". You can now return to the main menu and resume playing. (If you get RAM errors, for example when resetting, "F6" can be used to temporarily turn off all cheating, press it again to re-enable cheats.) Using Watchpoints: In the "Cheat" submenu, there is an option to "Configure Watchpoints". Select this and press "Enter", and you should see 20 lines of zeroes (you can configure a maximum of 20 watchpoints). Select one and hit "Enter". Select "Address" and hit "Enter", now type in the RAM address you want to monitor, and hit "Enter" again. Navigate down to "Length" and hit "right" to increase this to 1. If necessary, change the "Element Size" to 16 bit or higher (you may need to adjust the "Address" accordingly), and if you wish, change "Display Type" to Decimal. You can now return to the main menu and resume playing, although now you should see a little number in the top left. If you want to move the number to a different area of the screen, you can reconfigure the watchpoint and change the X and Y offset. To disable a watchpoint, set its "Length" to 0. Unfortunately, watchpoints cannot be saved; however it is possible to save a cheat of type "watchpoint". Extra Stuff: Hopefully, I've provided enough to help complete new-comers get started. If you want to have a go at finding and editing your own cheats, there is a pretty good guide here. One very useful feature that might be worth mentioning is how to bind a cheat to a key: select "Add/Edit a Cheat" from the "Cheat" submenu, and select the cheat. Navigate to "Activation Key" and hit "Enter". Now press the key you want to bind the cheat to, and return to the game. A final note: some of these cheats are of type "write if match", which was only introduced in MAME 0.111u1, and will not work in earlier versions of MAME. If anyone wants to ask questions or request cheats (please take note of the disclaimer at the top), or indeed contribute their own cheats to this thread, please feel free to do so.