Bfxr is an elaboration of the glorious Sfxr, the program of choice for many people looking to make sound effects for computer games.
Bfxr has moved in the direction of increased complexity and range of expression. All the buttons that you know and love are here, but there are some new things as well:
5 new waveforms : triangle, breaker, tan, whistle, and pink noise.
3 new filters : compression, harmonics, and bitcrusher.
Ability to lock parameters during mutation/randomization.
Expanded pitch-jumping abilities - good for arpeggiation effects.
Keeps your sounds and mixes in persistant lists.
Can reverse synths
Ability to link directly to sounds
You have full rights to all sounds made with bfxr, and are free to use them for any purposes, commercial or otherwise.
Focused on imparting a skill, lesson, or piece of information to its player that would be helpful to them in other aspects of life, such as a faster typing ability or knowledge about a period in history.