Early alpha testing of our first stories was done by family, because who else can you rope into trying something completely new like this? One of the comments my wife made was that it'd be nice to break up the reading of text and choosing of choices now and then with other activities.
That's how we started down the road of allowing authors to put minigames into the stories. Each minigame has to be custom programmed, and we don't want to put the effort into a minigame that is only used in one story. So each minigame had to be general enough that it could be used in lots of stories.
The first one we created was the combination lock. It's a bit of a stretch to call that a minigame, but it's way more fun to actually dial a combination into a lock than to click a button that says Open The Lock. To make the combination dial general enough, the author had to be able to specify the graphics for the lock, say how many tick marks are on the dial, that sort of thing.
It took a while and some testing to work out the kinks, but we eventually ended up with a pretty cool effect. You dial the combination in just like a regular combination lock.
The second minigame was the sneaking game. That was way more work than the combination lock. To make it generally useful in a lot of stories, the author has to be able to say what size the board is, what the graphics are, where the obstacles are, where the guards are and how they patrol, etc. Getting all that working right was a lot of work!
The end result was worth it, though. The sneaking game provides a fun, tense little break from reading text and clicking choices.
The original idea was to immediately end the sneaking game as soon as the Detective was caught, going down whatever path the author had specified for that. But early testers (e.g. my wife) said that most of the fun was trying again and again to get through. So we put the retry option in, where if the Detective is caught they can decide if they want to keep that result or try the game again.
The third minigame was the putting together puzzle pieces one. That one can be used for putting together pieces of a map, or a riddle, anything where you have to get the graphical pieces of something fit together in the right positions.
That one was a lot simpler to create than the sneaking game, thankfully.
If you have ideas for a minigame you think would be awesome for our stories, let us know!