FWIW, Wikipedia says EMC EM78 family are PIC clones.
Here's the Tetris ROM dump: www.seanriddle.com/tetrisrom.bin
I see a lot of tiles, background graphics, "Battle Garbage", and RAM check/ROM check diagnostics.
Here's a pic of the dumping rig: www.seanriddle.com/spaghetti.jpg
Tetris board is on the right with the CPU deglobbed and 33 wires soldered between the TSOP48 pads and a proto board with 48 header pins. PIC18F46K22 powered by 2xAA batteries drives the address lines while Logic 16 captures the data lines and a flag output from the PIC to make it easier to separate the bytes.