If this does indeed beat all the closed source models, then I'm flabbergasted. The amount of time and resources Google, OpenAI, and Anthropic have put into improving the models to only be beaten in a couple weeks by two people (who as far as I know do not have PhDs and years of research experience) would be a pretty crazy feat.
That said, I'm withholding judgment on how likely the claims are. A friend who developed NoCha [1] is running the model on that benchmark, which will really stress test its ability to reason over full novels. I'll reserve judgement until then.