What is it? a starting point for making Flash games that handles a lot of the tricky bits for you, like physics and savegames
Price and licence: free, you can sell what you make, no royalties
Makes games for: any web browser with Flash
Tutorial: Making a basic platformer(opens in new tab)
Case Study: Canabalt
Developer: Adam Saltsman
Play it: free, on Adam's site
How long does Flixel take to learn?
This is a really hard question for me to answer objectively - not because of the Great Marketing Potential but more because it's really really hard for me to imagine not knowing how to use it, since it was all built out of my personal tastes, etc. I think if you picked it up and set out to make a like arcade game clone with no prior knowledge you could probably get it up and running in a week or two, without any prior coding experience. To really get flixel singing would take a few more weeks at least, but ultimately there is just not THAT much in it to learn, really.
What prior knowledge or skills are helpful?
The most helpful thing would be C-style programming experience and/or some object-oriented programming experience. Neither are strictly necessary but Flixel is definitely informed by these practices and my experience with them. If you know that stuff then the learning time for Flixel is more like 1 or 2 days.
What can't you do with it?
Making 3D games is more or less out of the question (outside of duplicating the raster math from really old fake 3D arcade games or something). It's not really cut out for some slices of Flash game domain too - there is no built-in support for movie clips, for instance, and doing large levels with zooming camera effects is actually possible now but not really thoroughly intentional in the library's design. Flixel is definitely strongest for games with a relatively fixed perspective and film-strip style art assets.
How long did you think the game would take to make, and how long did it actually take?
Approximately 5 days, and approximately 5 days.
How much of the development time was enjoyable?
It was basically all completely awesome. Mechanically it is such a simple game, there weren't many rabbit holes to go down. The least fun part of the process was a few hours sunk on semi-successfully searching the web for some free sounds to use as fodder for the things I couldn't Foley .
How much did it cost you to develop, and what did that money go on?
Approximately $200, but that was for a plane ticket to Phoenix to attend a little game jam thing some friends were having. In retrospect, that was super important, but I didn't realize that at the time. Usually I spend a lot of money on sound, but I'd pretty much used up all my war chest for personal games at that point in my life, so I did all the sound engineering myself, and Danny Baranowsky wrote the music for free as a personal favor. Thankfully Canabalt did well enough that I was able to repay him for his contribution!
How well has it done for you financially, on a scale from 1-10?
The Flash version was probably about a 2 or so. The iOS version is I think more like a 7 or 8 maybe. We did an Android Humble Bundle which was practically a 5 on its own. I'm not sure if I'm supposed to add those up or average them or what! I give it a 5.2382 overall score.
If you could give your past self one piece of advice before starting to make the game, what would it be?
That is the one thing I've ever made where I think I would have nothing at all to say. Except maybe "go ahead and pay Danny ahead of time, it will definitely all work out." But then GOD who knows what would have happened? DON'T MEDDLE WITH THE PAST.
Flash games are still one of the most accessible ways for a stranger to go from hearing about your game to playing it, and Flixel is likely the best way to make one. Flash doesn't work on iOS devices, though. It's worth knowing that Unity games can run in a browser with a plugin for Firefox, or natively in Chrome. And Game Maker can make HTML5 games, which run in modern browsers without plugins.