Since its a MAME cab I think it is great you went with a non-original, yet tastefully chosen theme. Really like what you did with the artwork.
Thanks, at first I was thinking of going with Donkey Kong but I wanted 2 lots of controls so then I was thinking going with Mario Bros, then when googling artwork on the net I stumbled across Mario vs Donkey Kong.
Nintendo were well known also for their versus cabs and Mario and Donkey Kong are the oldest adversaries off all time in the video world.
I really liked the usage of the two different fonts used in the title and preferred the artwork over the original and also over the more modern 3D artwork.
I'm pretty handy and cutting and pasting in Photoshop and have made quite a few different themes for HyperSpin so I thought I'd give this a go as a theme for the cabinet.
Marquee - I'm really happy with.
Side Art - I like the side art but it kind of looks like Mario is on cloud or something, need to put him on something to make him look like he's on the ground.
Bezel - I need to find another picture of Pauline, the one on the left is too low in resolution, it will look a bit shabby when it larger, also would like include some love hearts like the original Donkey Kong but need to find a love sick Donkey Kong picture to make it work.

Control Panel - I'll probably redo this, the only thing I'm really happy with is the arrows and the Mario and Donkey Kong logos, perhaps I need to make the two different sides of the control panel different colours or something.
Maybe it will be a good idea to make the right joystick the P1 joystick. This way you will have plenty of space when doing single player gaming.
I'm thinking in games where you alternate between players one and two to have both joysticks mapped to player one, then you have a choice of which one you prefer to use.