I recently released the demo for "bang shoot." It's a minimalist fast-paced round-based retro FPS with a bunch of maps, modifiers and guns. You can play it right now for Next Fest.
The demo is roughly 30% of the full game, we have VOIP, text-chat, dedicated servers, and other cool things. In the demo, 20 maps, 8 modifiers (such as Third Person, Big Heads), and a LOT of guns.
It's not Chaos 2, but I think its fun.
Thanks, Frinky.