"Fun"

Something I was contemplating this weekend: Why would this game be fun, anyway?
I mean, I wouldn't code it if I didn't think I'd enjoy playing it at some point. But "fun" is such a weird, nebulous thing. If it's outside the mainstream, explaining why something would be fun can be a challenge. So what's the pull of playing an IF that's essentially a big farm sim?
It doesn't really have a plot as such, and certainly not a story as such, even in the extended design plan, which is the usual reason I give for playing IF.
Some things come to mind:
- Cracking the system. For someone else, who comes in from outside the game, there's a sort of pleasure in figuring out what needs to be done. I anticipate the main hurdle to be surviving the first winter - after that it'll probably get easier.
- Exploring the world. I expect the world to be relatively large, between garden, orchard, fields, pastures, buildings, and wild areas, and hope to have it change over time, which is cool.
- For genetics geeks like me, there's something kind of cool about teasing out what's inherited and trying to isolate the right gene combos to get what you want.
- There's the joy of seeing something you built over time change and grow (i.e. planting an orchard and getting fruit from it, seeing it blossom, etc.)
- There's the achievement piece - have you completed all the upgrades on the house? Put on a nice new roof?
- There's a time management piece - there's no way you can keep on top of everything. What are your priorities?
- There's sort of a curiosity/world building piece I should really work on - not that this is pure realism at all, but what would someone's options be if he/she was cut off with limited survival skills? And playing a game is more fun than actually doing it.
- Responsiveness/growth - this is sort of a world-exploration thing, but discovering what you can do. Since skills grow with practice, the player should have more opportunities to do stuff.
- And, of course, if there's anything Dwarf Fortress has taught me, it's that losing is fun. Hopefully it can be here, too, rather than infinitely frustrating.

I'm definitely concerned about the game becoming too easy after the first year. I can think of a few deus ex machina ways to slap up the difficulty level, but not many organic ways.
One thought would be to begin to introduce other survivors that need to be supported.
Another would be the increasing affect of wilderness - as the area becomes more fully abandoned, predators move in.

Either way, that's a long a way off, and definite supplementary material.