Quote Originally Posted by Talakeal View Post
For some more elaboration, the bounty hunters actually showed up during the battle with the sheriff and turned it into a four way brawl between the PCs, the Sheriff and his deputies, the Bounty Hunters, and the Zombie Horde, with the townsfolk caught in the middle. I had it set up to be sort of the big showpiece capstone battle for the campaign.
With the full admission that I don't even know what system you were playing nor at what power level to say how survivable this would have been, if a DM had thrown something that big at me for a one off campaign, I would probably have assumed they were going for the TPK/Epic Rocks Fall/Big Damn Heroes with Sacrifices outcome and probably would have taken wild actions too. A one shot and a campaign session have different unspoken rules, and one of those tends to be that a one shot can be deadlier, and players can take more risks (and use more of their limited resources) because it's not going to have long term effects.

Instead each PC decided to go off on their own crazy plan without communicating or coordinating with me or with one another. As a result we ended up with a TPK and the town overrun by zombies, which in retrospect I think was what the players had been going for all along.

I am still not sure why though.
And this is where for future games, you should pause and ask them. Seriously there's nothing wrong as a DM with pausing the game and saying "Ok folks, what's the plan here because at the rate you're going, you're all aiming to be pushing daisies in a few rounds." Sometimes miscommunication happens, you think things are going one way (and think you're conveying that to the players) and the players think it's going another way. When things start to go off the rail, it's usually a good time to pause things and figure out what's going on. Maybe they feel like they're being put in a no win situation, maybe they're feeling like they're being railroaded. Maybe they're just having an off day, or maybe they think zombies and bounty hunters and tyrannical sheriffs is a slapstick setup rather than a serious premise. Communication is always the key, and sometimes it's easy to get cut off from the rest of the table behind the DM screen and dealing with all you have to handle to run the game.

Up until my friend told me that no one wanted me to come back I thought they were just having an off night and that I was being overly sensitive or misreading their actions as disinterest / distaste in the game.
Like I said, I'd give it a couple days and open up communication again. It still could have been an off night, and just as you might have been misreading them, they might have been misreading you.