I got a Tactix game; it's a 1980 Simon/Merlin-type game from Castle Toy Company. The CPU is a NEC D557L, which is listed in the 1980 and 1984 NEC Catalogs. The 1980 book says it's in the uCOM-43 family, but the 1984 book says uCOM-4. Both catalogs say it has 2000 bytes of ROM, not 2048, although other chips are shown having 2048. It has a test pin that the data sheet says "connect to VSS", so I'll see what happens when it's connected to VDD.