Analytic theory, numerical simulation, and qualitative analysis of the threshold conditions, nonlinear dynamics, and spectral features of the superradiant emission and cooperative radiative behavior of a dense many-particle system in a low-Q Fabry-Perot cavity with distributed feedback of counter-propagating electromagnetic waves are given. Novel lasing regimes, from regular to chaotic ones, are found to be originated from collective spontaneous emission of active centers and may contain well-correlated or weakly connected dynamical spectral components. Various systems with extreme spatial-spectral density of radiating particles as active media of superradiant lasers are discussed, including those with almost homogeneous broadening as well as strongly inhomogeneous broadening of a spectral line. In the case of experimental verification, the phenomenon of CW superradiant lasing will be promising in the information optoelectronics and condensed matter physics, in particular, for managing novel oscillators with complicated dynamical spectra and for creating unprecedented diagnostics of quantum coherent many-particle effects.