What's a critical analysis of the play Warden of the Tomb by Franz Kafka?

The Warden of the Tomb is an expressionist play which explores neural interpretations of the self during the hypnagogic state. A hypnagogic state is the period of drowsiness before one falls into sleep; it is a state between waking and sleeping. Kafka was said to have suffered from hypnagogic hallucinations, which in turn influenced the nature of his writing. Someone who suffers from hypnagogic hallucinations often experiences what is described as an autoscopic reality.
During an autoscopic experience, the individual perceives his being and body from a vantage point outside the body. An autoscopic experience is similar to what we call an out-of-body experience; it is also described as the state when the individual sees an "imaginary double," another version of himself.
Now, let us define literary expressionism. This term essentially applies to literature that rejects traditional literary conventions. Expressionist literature focuses on subjective emotionalism, often distorting reality to make sociopolitical statements. Thus, expressionist literature is the perfect vehicle for exploring extrasensory experiences in the hypnagogic state. Those who, like Kafka, suffer from hypnagogic hallucinations often see an "imaginary double self" as a ghost or ghosts (just like the warden in Kafka's story). Some medical experts hypothesize that the perception of this imaginary double is a dysfunction of proprioception and kinesthesia.
Proprioception can be defined as how our central nervous system responds to our environment and drives our actions. For example, sensors in our fingers tell us when an object is too hot or too cold, which in turn directs our behavior. Meanwhile, kinesthesia refers to our body's awareness of space and how it moves or positions itself. Even when our eyes are closed, we are aware of the position of our limbs (whether we have lifted a leg or an arm, for instance).
In The Warden of the Tomb, the warden never sleeps; he exists in the state between waking and sleeping. In this state, his abilities of proprioception and kinesthesia are strongly compromised; he exists in a constant state of disorientation. The warden insists that he engages in "wrestling bouts" every night. His nightly activities with the "blessed ancestors" or ghosts seems to be the reason for his extreme enervation. The warden's nightly encounters represent his experiences during the hypnagogic state.
The warden's double selves alternate between different identities, the most prominent of which is Duke Friedrich. These surrogate selves, notably, do not respond well to light. The warden is able to defeat Duke Friedrich when dawn approaches, during which time the latter confesses his defeat. Essentially, the warden's job is to navigate between human existence and the "other" world. He serves the Prince by accepting only the best elements of wisdom from the "blessed ancestors" while simultaneously keeping out the worst. This is why he needs to wrestle with ghosts in the night.
The "imaginary double" has actual access to the Other, a world that is closed to humans. The warden, as a sentry between the Human and the Other, does not himself enter the spiritual realm. Instead, his imaginary selves do so. They bring back wisdom from spiritual worlds, and it is up to the warden to accept or reject that wisdom.
The occultic theme of a sentry between two distinct worlds (one corporeal and the other ethereal) constitute Kafka's exploration of paranormal awareness in the play. The cosmic doubles that ask to be "let out" or recognized are relentless. Interestingly, the warden's imaginary doubles are both feminine and masculine in identity. This schizophrenic conception of the self reinforces the theme of duality (doubleness) in the play. Note the Prince's dual nature, which is in a constant state of change:

The Prince has a dual nature. The one, concerning itself with government, wavers absent-mindedly in public, disregarding its own privileges. The other nature admittedly searches very painstakingly for a strengthening of its foundations. It searches for them in the past, delving deeper and deeper. . .

The warden's dual nature is certainly evident in his perception of "imaginary doubles":

STEWARD: The Warden of the tomb. One must probably be a stranger to size him up. Isn't that so, old boy, you little old screech-owl, you! Have you ever seen him flying through the forest in the evening, out of any gun's reach? But by day he ducks at the slightest move.

Source: The Mystical Life of Franz Kafka: Theosophy, Cabala, and the Modern by June O. Leavitt
https://academic.oup.com/brain/article/127/2/243/347826

https://www.huffpost.com/entry/hypnogogia-dreams-creativity_n_56c5d16ce4b0c3c55053de38

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2944142/