Checked out the raws, so here's some spoilers.
Only 4 years have passed in the other world, vs 15 on earth. ML actually didn't know MC had been killed (I guess getting transported back to earth removed all traces? idk) and assumed he'd just fled. He's apparently been searching for MC this whole time.
MC suspected ML might have been the one who killed him, but nope. ML IS pretty sus, though. He recognizes MC right off the bat and closes the distance between them insanely fast (forcing lots of kisses on him, hugging/holding onto him all the time, a random masturbation session in a closed-off library room with the typical "don't worry, I won't put it in yet but you're just so cute it's hard not to lose control" yaoi line). ML apparently liked MC even back when MC was 13??? There's this dream/flashback where young MC was getting his hair dried just out of the bath (so, nearly naked) and present MC notices that ML was looking at him like a predator with prey... so, um, yeah...
They skipped some pretty important stuff that should have happened before the cooking competition: one that inspired what MC makes and one that helps him technique-wise. I really don't see how this is going to work, unless they stick in some flashbacks while he's cooking or something...
Why'd they cut nearly all of his fight against the soldiers in ch36? It was so cool in the novel!
About the two untranslated bits of dialogue in ch8:
グレンほどでわないけど = not as many as Glen, though
俺の方がランク上なのに... = even though I'm a higher rank...