"This is thought to be entirely secure against the Meltdown and Spectre CPU vulnerabilities, which require speculative execution on branch instructions."
I must not be understanding Meltdown correctly and I know this is a joke, but I thought it was the malicious code that used speculative execution to (indirectly) read unauthorized memory. So in what sense is Branchless Doom secure against Meltdown?
You don't store your plaintext passwords in a modded version of Doom with a kernel scheduler hack to ensure it mostly gets dispatched on the HyperThread core neighboring the one your browser is getting dispatched onto?