I was playing Flexbox Zombies for a little while and really enjoyed it.
> This is a Mastery Game. Each section unravels part of the plot, gives you mastery over a new flexbox concept, and presents zombie survival challenges that force you to solidify your new skills like your life depends on it.
He also has a new one called "Grid Critters", which I'm unfamiliar with but it looks like it's a similar thing but space themed and for CSS Grid instead of Flexbox.
> This is a Mastery Game. Each section unravels part of the plot, gives you mastery over a new flexbox concept, and presents zombie survival challenges that force you to solidify your new skills like your life depends on it.
https://flexboxzombies.com [free]
He also has a new one called "Grid Critters", which I'm unfamiliar with but it looks like it's a similar thing but space themed and for CSS Grid instead of Flexbox.
https://www.gridcritters.com [paid]
His blog is also really awesome too: http://gedd.ski/