I've only ever played it singleplayer. One of the most fun times I've had with it was on Flatgrass, I spawned a Razor Train locomotive near the edge of the map, went back to the concrete platform in the centre, and used the Manhack Gun to attach a silly amount of Manhacks and Rollermines to the thing, until there were several enormously long, snaking tendrils moving like an octopus on crystal meth, with tons of small side branches. Some of them were reaching almost to the platform.
The Razor Train was spinning about like a plastic crate under the influence of the Gravity Gun. I then used the Flechette Gun to pour a constant stream of explosives their way, breaking the chains up, sending crazily wriggling air-snakes of Manhacks flying every which way. There were at least half a dozen chains, long and short, that flew so high I could barely see them.
There were massive clusters of Manhacks and Rollermines tumbling about all over the map, and by the time I was done, the place was littered with Manhack remains. (I could only pop the Rollermines with the RPG.) It took quite some time to prepare, but that was some of the most silly fun I'd ever had.
