Conventional wisdom dictates that it’s best to start with the most refined, precise possible example of your game before adding extra stuff. There’s a logic to this: Your extras depend on the core game and altering the core game will often mean discarding or at least mutilating them. If you design a really cool movement special ability before you’ve made sure your system for movement does the job then you’ll put yourself in a position of either deleting something that’s working great or having bad decisions at a lower level locked in.
To counter this you build the minimum playable version of your game, test and refine that until your core is great, then add things to the working core.
A lovely idea in principle, but how do you decide what the minimal viable version of your game is?
Let’s pretend you are the designer of Dominion (Unless you are Donald X in which case you don’t have to pretend) and have decided to work on the MVG before designing all of those fiddly special actions. What exactly is that?
Is it a game with only copper and estates? That’s enough to have a choice of what to buy every round and shows off the core tension between “I need points to win but points make it harder to buy stuff”
Or does it need to contain gold too? So you get that effect in which adding a lower value treasure is helpful early on but its presence will become detrimental later?
Or does it need at least one action card because they’re a fundamental part of the game and also running out action card piles is part of the game over condition.
Or does it need at least two action cards because the limit on how many can be played is part of the game and having one that allows +action and one that doesn’t is part of the core game?
The minimum viable game is a non-trivial problem. If you tried to refine the game from just having a copper pile and estate pile you’d either find you couldn’t make your supposed core fun to play no matter what or copper and estates would become complex in ways that mutated the game beyond all recognition.
On the other hand you could just as easily justify to yourself that you have to include everything for one reason or another which defeats the point of the exercise.
Personally I reckon it’d be somewhere around having the treasure and vp cards and 3-4 action cards that are intended as archetypical examples of common things players will do (Say Village, Smithy, Remodel, Militia and Woodcutter). But there’s no hard and fast way to say “Yeah, that’s the right amount of fancy actions for the game to be enjoyable so I can test and refine on that without getting bogged down in making others that might be made redundant as I change things”. It’s obvious that having none leaves you with something that’s not really much of a game, but for any particular list you could almost always justify removing some member from it.
So given those limitations how do you find the MVG for your own design?
Coming back to your games interesting decisions is never a bad move. If a game is a series of interesting choices, then the minimal viable game is the parts of the game sufficient to produce its most interesting choice.
Start by asking “At what moment will a player of this game go ‘I want to X and I want to Y, but if X then not Y but if Y then not X” Then once that’s identified look at what’s needed for that choice to work.
That’s not limited just to creating the choice, but also in making it have payoff. Sure the player has to have (at least) two options, but there has to be enough going on that it’s not trivially obvious which they should pick. There also needs to be a result that’ll let a player look back and see if they made that choice poorly or well.
Sometimes this requires things that are like the icing on the cake. It could be that the core of your game doesn’t work unless everyone’s got a special power or there are cards that create exceptions or whatever. That’s fine, your minimum game doesn’t have to be about “Destroy everything that looks like a sprinkle”, but it should manage “Use the minimum number of sprinkles”. If two different powers are enough to test that the core of your game is up to holding the weight of everything else you want to put on it then you don’t even need to design enough to get the game going at its highest player count.
Your minimum viable game might not be that minimal, in order to be viable, but it’s worth knowing what it is. Having a clear idea of what your core is, why it works, what’s critical to it and what’s you expanding on it will help with every other thing.
What does the minimal version of the last game you played look like?