Slavoj Žižek minimizes the ontological difference in his upcoming "Why Heidegger Made the Right Step in 1933".

What this also means is that ontological difference is not "maximal," between all beings, the highest genus, and something else/more/beyond, but, rather, "minimal," the bare minimum of a difference not between beings but between the minimum of an entity and the void, nothing. Insofar as it is grounded in the finitude of humans, ontological difference is that which makes a totalization of “All of beings” impossible - ontological difference means that the field of reality is finite. Ontological difference is in this precise sense “real/impossible”: to use Ernesto Laclau’s determination of antagonism, in it, external difference overlaps with internal difference. The difference between beings and their Being is simultaneously a difference within beings themselves; that is to say, the difference between beings/entities and their Opening, their horizon of Meaning, always also cuts into the field of beings themselves, making it incomplete/finite. Therein resides the paradox: the difference between beings in their totality and their Being precisely “misses the difference” and reduces Being to another “higher” Entity. The parallel between Kant’s antinomies and Heidegger’s ontological difference resides in the fact that, in both cases, the gap (phenomenal/noumenal; ontic/ontological) is to be referred to the non-All of the phenomenal-ontic domain itself. However, the limitation of Kant was that he was not able to fully assume this paradox of finitude as constitutive of the ontological horizon: ultimately, he reduced transcendental horizon to a way reality appears to a finite being (man), with all of it located into a wider encompassing realm of noumenal reality.

P. 22

That may sound familiar to readers of The Parallax View because essentially the same paragraph appears there on page 24.  ¶ 7:17 PM