Now, I know that my Credits blog post already thanks all the groups who helped make Flight Odyssey possible. However, that was kind of cold and legal, so I'd like to take this opportunity to talk a little bit about each of the services that were most helpful. The purpose is twofold: first, to give out some well-deserved credit, and second, to help other developers who are trying to build apps without a huge infrastructure of support.
Let's start off with Clker.com, one of the most crucial resources in my search for images. Clker.com provides clipart/vector images licensed under CC0 (effectively public domain). It has a huge variety of images, and the price is right! The majority of my images come from this website, so I am incredibly grateful.
That said, let me point out a few caveats that may be of aid to other developers. First of all, the search engine built-in to Clker.com is pretty awful. My recommendation is to just use Google Images, but limit the search to Clker.com using the advanced search options. The other major issue is the ads. When I initially found Clker.com, I was using Chrome AdBlock, so I didn't realize that this was a problem. However, as soon as I switched to Firefox, I suddenly realized the website's ulterior motive in providing this great public service: lots of ads! (In fact, I was so surprised by the ads that at first I though they were being inserted by a virus on my computer.) Related to this is the fact that many images on Clker.com are actually downloaded from openclipart.org, so it may pay to try that site as well and see which you prefer.
Next, Bitbucket. I hate to admit it, but this is my first project where I've used a formal version control system. I can assure you wholeheartedly that I will be using it for my next project as well. At least once or twice I was spared from hours of work by a backup in Bitbucket, and several times the reassurance that the backup was there let me be more aggressive in making changes. To put it bluntly, version control is awesome, and Bitbucket implements it really nicely. Not only do the provide you with free private repositories for up to 5 users, they also have a nice GUI (SourceTree), a decent issue tracking system, and everything you would expect out of a paid Version Control system (despite being free). One caveat: they don't have an official mobile app or a mobile-friendly website (helpful things when testing on devices and reporting issues), but BitBeaker is an Android app which interfaces through their REST API and works nearly as well as an official app would.
Another major issue I've faced in my project is performance. Some performance issues, of course, are related to memory consumption, while others are more complex. One tool, though, that I believe has greatly improved Flight Odyssey's performance is TexturePacker. I first discovered TexturePacker when I read this article/video. Just like Corona SDK, that video made some pretty bold claims about the performance benefits of TexturePacker, but they appear to be true. I'll admit I was skeptical at first, particularly when the initial impact of the software was to increase texture memory usage by a factor of 6 (since all images had to be loaded, not just the ones in use). Nonetheless, when I ran my app on a device, performance appeared to have dramatically improved. I still don't really know how that worked, but I suppose the theories presented in the video must be accurate. Not only does TexturePacker improve performance, it also provides a better way of organizing sprites, unlocks several features of Corona SDK that are only available with sprite sheets (like easy animations), and can decrease the size of the app. The biggest drawback is that it costs $40 to get the full version. Fortunately, you can use the essential mode for free (though it lacks some of the optimizations) and bloggers/framework developers can get a free license for the full version.
Some other helpful tools include GIMP (a great way to fine-tune the free clip art from Clker.com for a specific purpose), Paint.NET (like GIMP but lighter weight), ImageAlpha (for image compression), and Notepad++ (once I discovered that you can create a workspace in the sidebar, I never had to use another text editor).
And of course, this list could never be complete without Corona SDK. I've mentioned before how impressive it is, to the extent that it inspired me to create this app, but it can't hurt to repeat it.
That's all, and thanks for reading! If you would like to suggest any other helpful tools for independent game development, feel free to leave comments!