Back in the 00s I strongly associated Havok with Oblivion, because... Well, it was in your face all the time, with clutter flying all over the place, physics-based traps, ragdoll bodies and skeletons exploding in a dozen pieces.
And it was very, very broken, especially in crowded spaces. Still happened in Skyrim by the way. I used to joke about how "Havok" was a perfect name for that mess... But that's probably Bethesda doing Bethesda stuff with it.
I was aware it still is in use, spotted it on many credits. The fact it's been used as a base (even with another custom physics system on top of it) in Tears of the Kingdom tells me the stuff must still be quite solid.