I liked it. It enhanced the atmosphere of the game IMO.
The English in the game isn't modeled on "Old English," it's modeled on Early Modern English. Early modern English ( "he taketh") was the language of Shakespeare, spoken in the late 16th- mid 17th century. It's a bit strange to us today, but it's basically intelligible to modern English speakers.
Old English was spoken in England from the Germannic invasions (mid 5th century) to sometime after the Norman conquest (mid 11th century). It was very Germannic, and it would be almost totally unintelligible to modern English speakers.
I thought Old English was actually Gaelic, not Germanic. Or am I thinking of Middle English?
You're thinking of what the original, Celtic British people spoke before the Germanic invasions.
Remember, the terms "England" and "English" come from the name "Angle", one of the major Germanic tribes that invaded the British Isles (the Saxons, the Jutes, and other Germanic tribes also took part in the invasions). Their part of the islands became known as Angle-land (later England), and the Angle language, which started an Old German dialect, became known as English. Old English was mostly Germanic (although it was undoubtedly influenced to some extent by the Celtic language of the British predecessors.)