In these kinds of games, the programs tend to be very small and you only need a very small set of functions which can be made opcodes rather than explicit funct

In these kinds of games, the programs tend to be very small and you only need a very small set of functions which can be made opcodes rather than explicit function calls. You can often write the VM in 2k or so and have programs of only a few dozen bytes, while a standard vm would be ten or a hundred times the size.