I agree that it's neat to have software synths that can run in the browser nowadays, but this isn't really a good TB-303 emulation. The accent doesn't have a slow enough attack to create the "wow" effect, which is a fundamental aspect of getting any random acid line to sound properly 303ish. Not to take away from what it is, but for a synth that has been cloned and emulated as often as the TB-303, your description is overselling it a bit.