A downloadable game.
Hell Grinders does exactly what you need: gives you the framework to run a couple hours of brutality with extreme 'heroes' shredding hardcore monsters that have just enough crunch to make them feel interesting without overwhelming. A good entrypoint into LUMEN and a great system for running a game with a heart made of boomer-shooter nonsense.
Slamming a Surge cola before playing is about the only way you could make this better.
