real hardware

Anyone know who in the uk can look at this? Background sprites are repeated as if it can’t load all. In test I get flashing purple screen. Thanks

I have seen a few videos on youtube where people have real arcade pcb's running light gun games and they are somehow playing them on a regular tv screen with the real arcade light guns. I would like to know if anyone knows how this is possible. The link below is Lukemorse1 playing Crypt Killer...