About Havok Physics

Cross-platform support for X360, PS3, Windows, PS Vita, Wii, 3DS, Android, iOS, Mac OS X, and Linux.
... formerly supported GameCube, PS2, PSP, and Xbox, but these are no longer listed as officially supported.

Major competitors for Havok are ODE and PhysX, both of which are available free of charge unlike Havok.

Havok can benefit from GPGPU via OpenCL for processing but can run without it (as it originally did).

Initially developed by Havok based in Ireland in 2000. Nearly all C and C++ source code for computer platforms was made available to licensees for learning and improvement but remained proprietary.
Company was sold to Intel in 2007
Sold to Microsoft in 2015. Microsoft made it clear that the would provide licenses to "the AAA games industry" but was unclear as to including games for other platforms besides PlayStation, Wii-U, Xbox, and Windows.