Venezuela TheMrBenpulido released a Quake 4 Gamepack with Quake 2 aesthetics and graphical "enhancements". Inclused all Quake 4 missions. You will need Kmquake2 or Vanilla QUAKE 2 with unofficial patch 3.24 in order to run it.

If you'd like to give it a shot, you can download it via ModDB. Comparison screenshots and gameplay video can be found here

Other links: TheMrBenpulido, Download