Vorpal Blade should always decapitate Medusa. When this happens, it produces a “Medusa head” comestible, which is a unique, unwishable item which could either confer stoning resistance when carried or, like in the myth, be used to stone monsters at range.

An alternative, to make it more broadly accessible, is to allow any bladed weapon used in melee to decapitate Medusa, and only her, on a critical hit (while Vorpal Blade will decapitate on any hit that lands).

Add more alternate Medusa level variants with unique monster threats: Echo and Synesthesia. Both monsters should be equally as threatening as Medusa, with a corresponding weakness to something fairly common by late midgame (as Medusa is weak to reflection and blinded heroes).

One proposed effect (for either Echo or Synesthesia) is to be stunned or damaged by loud noises like drums. Another proposal is that noise is Echo’s strength: she is alerted by noise and turns any noise around her into damage thrown at the hero.

If silver dragon scale mail is your only reflection source, or more generally if your only reflection sources come from your shirt and/or body armor, wearing a mummy wrapping over this prevents Medusa from seeing her reflection (though you are still considered to have reflection in all other respects).

Some Medusa buffs:

• Allow her to swim. (She can already fly, so this may not do much.)
• Give her a wrapping attack, flavored as crushing coils, which could possibly drown you.
• Her gaze has a reduced effect if you have reflection and not blindness, but not zero effect. Perhaps it begins slow-stoning rather than instant stoning.

5% of the time when Medusa is decapitated, she drops a “head of Medusa” item which can be wielded and used to petrify monsters, but only if the hero is blind (attempted use of it when not blind will petrify the hero).