There's a growing trend of official solo variants for board games, and as a person who often only has time to play by himself, I couldn't be happier with this. Having played my share of these, solo variants are a nice nod to those fans who sometimes can't gather enough people to enjoy the game at its peak. Whether they're official or custom-made in BoardGameGeek, solo variants increase a board game's replay value, and are as equal as any other mode of play.
Which is why I must insist - PLEASE don't feature solo variants as Kickstarter stretch goals.
But Wait, There's More!
Stretch goals, for the most part, are used as mechanisms to continue funding growth throughout a Kickstarter's campaign. They're there to entice current backers of more additions that would be possible now with growing funds, and to lure potential backers, offering what their contributions will give them when they sign on. It's a mechanism that rewards backers with more content the more money the campaign raises.
Sometimes these are calculated expenses, things that truly would not be possible
A Bit of a Stretch...
Along the same vein, adding a solo variant is an adjustment to the number of players. To me, it plays a large contributing factor on whether I'll purchase/back a game I'm interested in. It's something I (and, hopefully, the designer) don't take lightly. To place it in a stretch goal category (whether tacked on or intentionally separated to boost backer support) feels like the designer's still have some parts of the game covered up in blue tarp, waiting for the right moment to spring it on backers in a "voila" moment.
While having extra players or solo variants sold as separate expansions is nothing new in the current board game market, they feel a little different in the crowd-sourcing field. As I've said before, Kickstarter projects are always a risk - nothing's guaranteed, and should never be treated like a store. You're backing someone's project which may or may not be fully realized, including whether or not player counts and/or solo variants are done. Personally, I would be more confident in a board game where the solo variant is there from the start, or is at least worked on before the campaign begins. To suddenly create one and add it hesitantly as a stretch goal is ambitious.
Giving the Full Game
When you have a solid game and are ready to receive funding for it, you want your backers to remain excited for what's to come. So it's natural to assign things like better components, better quality, and special cards that will enhance gameplay as additional stretch goals. For better or worse, stretch goals exist and continue to drive certain campaigns up in funding. But when you start to add things that can fundamentally change the gameplay to more drastic levels at the last minute, it won't look as promising as if you had it ready all along. And even IF you have a solo variant all ready and tested, don't hold out on us and dangle it like a piñata in front of us, especially when the campaign's funded. Hopping on board from the start because it offers solo mode is much more satisfying than hopping on board 5 days before the campaign is over.
I won't lie...I may have, in the past, jumped into KS projects at the last minute when they introduced a solo variant. But not so much now. If you're going to do a solo variant, make it work well in your game, or don't include it at all.
And please. Add the solo variant in from the start. I want to play your game, no matter what.