Your game can be developed for any platform. Windows, Linux, OS X, Homebrew systems, etc.
However, it is worth noting that most entrants use (or have access to) Windows XP. To get the most possible votes, you should have a way for them to run your game (port, Py2Exe, Emulators, etc).
To be fair to entrants not running Windows, ports can be done after the deadline. You still must submit your version for whatever platform your default is by the deadline.
Any readily available compiler, library or middleware can be used to develop your game, so long as it meets the following requirements. For custom libraries, see below.
Generally speaking, this means any free and open source compiler and library is allowed, in addition to most readily available game creation middleware.
This is not meant to be a comprehensive list, just some examples. If you can't find what you're planning to use, find something similar. Wherever that lands is where your choice should too.
Again, unless a Non Disclosure Agreement is in effect, it's a safe bet it's allowed.
To be fair to users not opting to use 3rd party libraries and middleware, you are free to write or use your own custom library for the competition. Custom libraries must meet the following requirements.
It does happen that some people run late in declaring their libraries, and it's not like you can get the time spent in preparation back. So you are allowed to declare a library after the start time. We do require that you tell us you're using a custom library, and provide some details as mentioned above. We realize some middlewares like Unity and UDK may provide a technological “unfair advantage”, so unless your entry is in contention by the community, we'll let most lackluster declarations pass.
You're free to use any tools for content creation you have available to you. All content must be created during the competition.
No borrowing content! No clip art, stock photos, or previously created/acquired graphics.
There are no restrictions as far as what tools you can use to make your art. You need to draw it, scan it, model it, and/or texture it during the competition. Using reference that never makes it in to the game is fine, but don't trace. :) Note, if you are tracing an image you took yourself during the competition, it is ok to trace.
Fonts are allowed. You're free to use any font you're legally entitled to. Fonts are meant for text output, not as base for graphics (so you can't get around the 'no clipart' part by using windings/webdings/dingbats and whatnot).
Photography is allowed, as long as you take the photographs during the competition.
Given music's reliance on sampling and sample use, you are free to use any public domain sampled or virtual instruments you have the right to. This includes percussion, drum loops, or sampled instruments (piano, guitar, strings, synth, etc).
No pre-made voice overs or clips (“Oh yeah!”, “Move it move it”, actual lyrics, etc). The exception is choir samples are allowed, since they're used more like a instrument than a voice over.
Sampling (recording) anything that isn't copyrighted material is fair game during the compo. The voice of your wife, dog, cat, or the neighbors stray duck.
Raw library samples for sound effects are discouraged. Layer them, reverb/compress/EQ them, create jingles with sounds. Many sample library license agreements disallow the raw use of samples, so you should be doing this anyways.
Synthesis is encouraged. You're encouraged to modify presets in some way, instead of using them like raw library samples.
Sampling (recording) is encouraged. Pick up the mic, and record yourself making bleep and bloop sounds, or saying something profound.
DrPetter made an easy to use Sound Effect synthesis app, sfxr.
Some alternatives we've recently become aware of include Melody Raiser and Wave Raiser.
Open Office, Excel, map editors, 3D modeling or motion tracking software. Whatever you have, use it. Just make the content during the compo.
For creating timelapse videos and other extras, see the Log Tools page.