I'll have to go have another look at Beowulf, but broadly speaking - it seems like Beowulf is going to aid Hrothgar by defeating Grendel; whereas in Predator 2, we're two thirds of the way into the movie before Harrigan has the faintest idea what he's dealing with, and it's generally to stop the Predator rather than specifically helping anyone.
The motivations seem very different.
Yeah but don't you see; at the point in the movie where we enter the slaughterhouse scene, Gary Busey is now archetypal Hrothgar, and Harrigan is now Beowulf...I don't think its intended to add up every little detail, that would be too as Ridley Scott says "on the nose" and ultimately in bad taste. But the stories do echo each other quite a bit and I think its being acknowledged.
I just rewatched Predator 2 and had the same idea about the last third of the movie being a homage to Beowulf, then went searching to see if anyone else had already pointed this out and found this forum. The BEOWLF logo seems like an obvious wink from the director, but there are enough parallels that once we noticed the similarities, my spouse who had never seen the movie was able to predict things like that Harrigan would somehow cut off the Predator's arm, that the Predator would run away after being injured, that he would end up in some kind of hidden "cave-like" place, and that there would be something bigger and scarier in the "cave" or wherever the Predator holed up after losing its arm and that Harrington would have to have a final epic battle. The Predator spaceship lair is also underground, difficult to get into like Grendel's underwater cave, and holds more dangerous Predators.
Other things that seem too close to be coincidental:
- The last part of the movie starts after Harrigan meets up with King Willie the leader of the gang that has been terrorized by the Predator
- Harrigan heads to the warehouse, which is a large open space architecturally a lot like Hrothgar's Great Hall, where he teams up with warriors (and a leader, maybe a stand-in for King Hrothgar but I think more like the jealous Unfurth) - the Predator then kills a large number of warriors whose weapons are useless against it, as Beowulf's warriors weapons were useless against Grendel.
- Harrigan cuts off the Predator's arm with the Predator's own weapon, just as Beowulf tears off Grendel's arm barehanded. Also, regular swords cannot hurt Grendel, just like all the human weapons cannot harm the Predator, so it has to be the Predator's own weapon that is turned against it..
- Similarly, Harrigan needs to use an otherworldly weapon to defeat the Predator in the ship, just as Beowulf has to use a sword that he finds in the cave to defeat Grendel's mother and finally kill Grendel. In Beowulf the sword is destroyed in the process, and likewise Harrigan does not get to keep the Predator's weapon
- However, Beowulf does end up with an heirloom sword as a reward for victory over Grendel and Grendel's mother, and Harrington is given a heirloom flintlock after his victorious battle in the Predator's lair.
Certainly the elements are mixed up (or remixed) in Predator 2, but there are just too many elements that match details from the Beowulf poem for me to think it's a coincidence, especially with the visual hint of BEOWLF provided in the film.