I'd not spotted this before but BoardGameGeek run a number of games design competitions, including an annual one for print & play games using just nine cards - plus dice and counters already to hand. I found this after reading about another solo game called Under Falling Skies - the winner overall from 2019.
Rather remarkably, this is a card game version of Space Invaders! And it's really clever. It has a dice placement scheme where you generate power, scramble jets to shoot down the invaders, and develop the research that will ultimately defeat the threat. So you win by getting to the end of the research track and lose by your base being destroyed or the mothership advancing down to the final row.
Seven of the cards are lined up above each other to represent the alien invasion airspace and the player's underground base, which can be further excavated to provide the necessary extra placement spaces to fight the aliens. Each of these cards is reversible to make 7 levels of increasing difficult. Another card is the research track (also reversible) and the remaining just shows the name of the game.
It's fun to play and quite hard. Some challenging decisions to make as using your high dice to generate power or make stronger attacks, results in the alien ships advancing down the same number of pips, so there's always a trade-off to be made. Definitely recommended and apart from the cost of ink, it's free!
I thought I'd check out #2 from that year - which was also a solitaire game. It's called
12 Patrols and is more of a puzzle game. You have to place 9 cards (from a set now expanded to 12) in turn into a 3x3 grid, and then place Knights (D6 in three different colours) and Footmen (counters in the same three different colours) in the spaces between the cards, such that all the requirements on the edges of the cards are met e.g. in the rest of the row there are 2 different colours, or three items in total, or dice that sum to 6. Each of the 12 spaces has to have a patrol - it can't be left empty. Requirements on the edges of the cards that form the outside of the 3x3 grid are ignored.
It's tricky. Even once you've got familiar with the cards, it's still possible to get to a point where you can't place one of the final cards successfully, or you might not have the right combination of dice or counters left. But with more thoughtful placement of cards and a little bit of luck, solutions are achievable. I got this one on my fourth attempt.
As you can see, the artwork is rather special too. I think I shall dip into this list of games again. And look at the
2020 winners as well!