plustest.dsk has some "missing tests" but in fact there are the prefixes : CB, DD, ED, FD, used to launch other areas of instructions.
HALT is the only one instruction that will be allways always OK on plustest.dsk instruction timing testbench. As this instruction cannot be timed.
Megablasters seems running fine on r005.8.16c29. Using 4 disk version of Megablasters (old one), sometimes bombs doesn't explode, it's normal : in this case you have to press the second fire button (gameplay...)