The aging fx and other makeup is spectacularly bad, but I think it's tuned to home CRT tv sets of the day, so e.g. most everyone's in near-mime whiteface. The stammering and tics are an academy award unto themselves, this was pretty daring in the day (moreso today), and there may have been showboating here and there, contributing to a heightened theatricality. It was however central to the plot (Claudius not taken seriously and so not...poisoned).
One more thing, the ladies in particular were bewigged and madeup to uncannily resemble the encaustic [hot wax +pigments] portraits on Roman mummy sarcophagi (after the Egyptian fashion), which we have several splendid examples in a museum here.
EDITED: 21 Apr 2022 12:49 by DSMITHHFX