As far as I understand, Monty Python Fluxx is a separate game, not an expansion pack, that doesn't require the original Fluxx deck to play. But can it be used with the original deck - can it be used to supplement the original cards, or does it not work like that?
(This related question What are the differences between the Fluxx games? didn't quite answer my question.)
You certainly can just shuffle the decks together, try to play a game with them, and see what happens. The core rules of Fluxx are always pretty much the same, after all.
However, everything I've heard from people who've tried something like this suggests that, for maximum enjoyment, you'll probably want to start removing cards that don't work well in the combined game; or adding your own homebrew cards that will work well in the new game.
I'm not very familiar with Monty Python Fluxx, but I've played a bit of Zombie Fluxx - and it's pretty well optimised on its own. I could add my basic Fluxx game into the mix, but then the zombie theme would be much diluted. It would be much harder to assemble a critical mass of zombie cards to achieve one of the zombie Goals - or indeed the non-zombie cards required for a base set goal.
But in the end Fluxx is a game that it's best not too take too seriously. If all you're after is a nice long, random game with the possibility of unexpected interactions between cards from different sets, then I don't see why you wouldn't want to at least give a mega-game using cards from multiple expansions a try!
Can?
Yes.
Should?
No.
The only Fluxx sets with significant goal & keeper overlap are Fluxx and Family Fluxx; certain keepers are duplicated. Those two can be mixed, and mixing those two isn't a clear "Should not"... but the others, they definitely fall into "should not."
Such mixing definitely lengthens the game, as needed keepers are harder to acquire. It also reduces the skill factor and increases the luck factor of victory.
If, however, you simply want to mix the new rule cards and action cards, playing with only one set's goals and keepers, that does work somewhat better. It still potentially lengthens the game. (See note.)
Note: I say potentially, as the shortest game I've ever played was a combined Fluxx/Family Fluxx game. First goal was runny chocolate, I had sun and several other keepers, and the 1st player played "Play all"... and played a chocolate. I drew, got "Steal a keeper", stole his chocolate, and played my sun, thus filling the goal, and winning, 2 minutes into the game.
You can definitely use multiple Fluxx decks together, but it will slow the game down - different games use different Keepers, so it will take longer for players to get the right combinations together to meet Goals.
The biggest problem with combining Fluxx sets is that it's more difficult to achieve goals. Most versions of Fluxx have 100 cards, and a particular goal usually requires 2 Keepers (so there are 97 cards that are not relevant to the goal). If you add another 100 cards, now 197 cards are not relevant to that goal.
To try to mitigate this, our group has implemented the following houserules, and been pretty happy with the results:
We have found that this works reasonably well even with sets like Monty Python Fluxx and prevents a combined game from slogging.
