Defold is a 2D game engine from Midasplayer Technology AB, an affiliate to King.com Ltd. It is currently in beta stage.
Ranked in these QuestionsQuestion Ranking
Pro Easy to learn
Defold uses Lua, which is regarded as an easy to learn language by most.
Pro Completely free of charge
Software and online dashboard are free of charge.
Pro Good combination of visual editing + code (Lua)
You can do a lot with drag and drop, but you're not limited -- the code (Lua, which is easy to learn) allows you more power than just visual editing usually gives you.
Pro Fast results
Going from idea to result is very important for the creative process.
Pro Very performant
Being crossplatform it is important to work on low end devices.
Pro Visual editor
Pro Easy and fast export for various platforms
Pro Source code available
You can download and modify the source code of the Editor and the engine for free.
Pro Great community
A very active and friendly community in forums.
You can invite friends from the dashboard and create games together.
Pro Hot reload
It allows you to change scripts in a game while it is running live. Common use-cases is to tweak gameplay parameters or to perform debugging on a running game.