Just playing with this further and I think I've found the trigger - if I go into the main menu -> game settings -> advanced -> Mame and then turn off the rewind option then both Rainbow Islands and Berserk run fine. As soon as I turn that option on then they both bail straight back to the menu after the rom copyright screen.
@stuart - is that on a Pi1 or Pi2 ? - a clean install on both shows that they are working on my Pi1 but not on my Pi2
I think you can add Berzerk to the list - so I suspect there will be more titles affected
I posted about the same issue with rainbow islands - however, the problem only seems to affect Pi2 and not Pi1
I am experiencing problems with the 4.0.0-beta1 MAME078 core on the Pi2 which do not appear to be an issue running on a Pi1. A specific example is Rainbow Islands (rainbow.zip) - This appears to work fine on a Pi1 with the MAME078 core in both 3.3.0-beta17 and 4.0.0-beta1. However, this runs fine in the MAME078 core in 3.3.0-beta17 on Pi2 - but using 4.0.0-beta (MAME078 core) it gets to the ROM copyright screen where you have to OK it will return straight back to the ES menu and never get any further into the game. This may not be the only ROM which is having problems. Do others experience this issue ?