Table for one
Playing Donut Deck solo
There is no puzzle-style solitaire variant. There is a full game you can play alone, which is not the same thing — here is the difference.
The honest answer
If what you want is a designed solo campaign — a scripted opponent, a difficulty deck, a score to beat across a series of scenarios — Donut Deck does not have one, and pretending otherwise would waste your evening rather than mine.
What it has is a competitive game where every seat is optional. Sit down as the only person, fill the other seats with bots, and you get the whole game: same decks, same scoring, same variants, same 15 minutes. For a lot of people that is exactly what they were asking for.
Why that works better than it sounds
Donut Deck has no hidden information worth hiding. You cannot see a bot’s tray and it cannot see yours, but the whole argument of a turn happens on the board — which flavour is running out of room, which seam is one card from sealing, who is close to the Final Lap. A game against a Hard bot asks you the same questions a game against a person does.
It also means a solo game is not a lesser version to be graduated out of. The board you learn to read alone is the board you sit down to with three friends.
How to set one up
Take one seat
Open the game and leave yourself as the only person at the table.
Fill the rest with bots
One bot for a tight two-player game, three for a noisier board where boxes seal under you. See what the three levels actually do.
Pick something to make it awkward
Perfect Match against one Hard bot is the hardest thing in the game. Coffee’s For Closers against three bots is the loudest.
Playing the physical copy alone
You can, in the way you can play any two-handed card game alone: deal both trays face up and play each seat honestly. It is a decent way to learn a variant before teaching it and a poor way to spend an evening, because you know both hands. The browser version solves that for free.
Next: the AI levels, strategy, or playing with other people.