The Darkness - 17 card solitaire game

i like this idea, simple but (possibly) very hard to beat. you may need to be a bit clearer on what " impossible to win means" but im sure you have that in the rules. as a gamer with very few friends who play tabletop i love a good solo game, and it is surprisingly hard to find a decent one that isnt a) pricey, b) fiddly (so many pieces and rules to make up for the missing players) or c)a multi player game made solo. good luck with this one.

This sounds like an interesting start. About how to add more depth to the game, I don't have any specific suggestions but I have a few general suggestions:

1) Ask other people to playtest it and see what they think. Be open to their feedback and see how the game develops as more and more people try it.
2) Take a break from it and come back to it later. You may get other ideas just by letting it percolate in the back of your mind.
3) Try some of the brainstorming techniques outlined in books such as Thinkertoys by Michael Michalko.
4) Don't feel like it has to have only 17 cards. That's a really limited number that is going to make it really hard to add any depth with.

This is an intriguing little memory game, but it's a bit too easy. Once you identify the four Braves, it's relatively easy to get them into position safely. Flip cards out of the Watcher's range for two movements, giving you time to look at them and flip them back over. Once a Brave is identified, move it into position and repeat.

Points I would focus on:

-Unlimited turns makes the above solution easy to implement. Limit the turns or find an additional loss state.

-Since there is no compulsion to flip cards, cards are never at risk. A mandatory flip somewhere in the process would necessarily endanger the Brave cards. Perhaps the Watcher puts pressure on the card he's next to, flipping it over automatically or conditionally.

I'm intrigued to see what you do with this. Keep us updated!

the idea of aditional loss conditions is a good one, you can always add them as an optional extra level of difficulty (for extra pounts maybe). 1 idea might be if you have 4 unnamed, of the same colour in a square, columb/row etc. for more depth with the same amount of cards each card could have aditional states depending on its orientation ( face up/down, on its feet/head) this could give them double end points, half end points, can only be turned by darkness, cant be turned by darkness, can only/not be next to a certain colour etc etc.