"Each game is divided into five sixty-second rounds. In between each round, this slot machine in your HUD activates, changing the rules set for the next round. One minute you're rolling around in an absurdly large tank crushing Hell Knights beneath your treads without a care in the world, the next you're desperately fleeing at half speed while firing Wolfenstein weapons futilely at an invulnerable hellbeast, then the next you're flying around lobbing petrol bombs at Imps. The choice isn't yours, it's all up to chance and a cruel, unforgiving RNG. And if you survive all five rounds...?"
A gameplay video as well as further information, screenshots and a download link can be found over at ZDoom.org in the development thread. Reelism is something that you will like or hate... well, I like it!