When I spoke to Stephen "increpare" Lavelle last month, the creator of brainy puzzle game English Country Tune described his oeuvre as "pushing stuff around" games. That's a good genre! It's in my top ten, alongside "making people fall down" games, "staying inside the lines" games and "steering balls into holes" games.
Now increpare has expanded his work in the field by releasing PuzzleScript, an open-source puzzle game engine that makes it easy to create "pushing stuff around" games and all manner of other puzzles. It's easy enough that successful indie designers like Terry Cavanagh and Bennett Foddy can make games in it in between the hundreds of other games they're producing in any given second.
The PuzzleScript website gives a basic introduction to the language. Here's a line that means, "If a player is trying to walk into a crate, try to push that crate.":
[ > Player | Crate ] -> [ > Player | > Crate ]
The engine is powered by HTML5, which means every game runs in your browser without a prior install, and you can view the source codes for the game you're playing and edit it in real-time. If I was to play just one, I'd recommend Farbs' (of Captain Forever and Card Hunter) Dungeon Janitor, which has you tidying up some happy slime. Porpentine made her own recommendation yesterday.
PuzzleScript is easy enough to use that you can make a game in it quickly even with no prior game making experience. Check out increpare's PuzzleScript tumblr for more examples of the creativity that happens when you make game development that little bit more accessible. Oh! Also, read this thing Cara wrote about one of increpare's other games, Slave Of God.