i think part of the confusion is that mame-libretro is a rom folder installed in ~/RetroPie/ where you put your roms in for any of the libretro MAME cores. eg, this folder is used for the default lr-mame2003 core that uses the 0.78 MAME romset. however, there is also a 'lr-mame' ("libretro-mame") emulator that is an experimental (not installed by default), that uses the current (or close to) MAME romset.

in any case, put your 0.78 roms in /mame-libretro/, use lr-mame2003, and if you get any issues please post the verbose log as instructed.

@grant2258 I started a new topic on this to not clutter this one.

@grant2258 Hi Grant - yes I think I've realised that this is the problem. The default RetroArch setup creates a virtual gamepad and binds both virtual gamepad and keyboard. I think the problem with Defender is that these mappings overlap - so the virtual gamepad is triggering as well as producing a keypress, and these are both bound to different things (eg thrust AND fire).

Thanks for your help!

@quicksilver will do, thanks!

Currently running 4.4 with latest updates, Pi 3 b+

I'm resurrecting this topic because this doesn't seem to work anymore. I put mame2003-cheats = "enabled" into retroarch-core-options.cfg but no 8-way movement.

This WAS working last year so some change has been made to mame2003 since. Can we please put this back the way it was? I don't think anyone here wants to have to use mame4all.

Yes, the method to make two-handed "tank" controls work on a single 8-way joystick does not require any cheats, just a clever set of controls mapped to what is sometimes called a "tankstick". The mapping makes use of <CODE_NOT> logic where you are actually excluding certain input combinations. MAME lets you setup mappings like this by using a double-tap of an input while in the GUI menu which changes it to a <NOT>, so if you do several inputs in rapid succession, before MAME accepts an entry, you can make some combinations that work in interesting ways.

Here's a mapping for a single 8-way joystick to control two tank sticks like Battlezone:

Game Control Mapped to Right/Up Up <not> Right or Left <not> Down Right/Down Down <not> Right or Right <not> Up <not> Down Left/Up Up <not> Left or Right <not> Down Left/Down Down <not> Left or Left <not> Up <not> Down

There is an odd situation for Keyboard controller users in lr-mame2003 that requires you to first set all retroarch inputs to NUL using a per-rom config file if you want to do this. You can read about it here.

Thanks fellas

I know I'm being lazy - I'll have a read. The start of the learning curve is always the most painful!