The implementation of the Bologna Process (BP) did not go as smoothly as the Bologna Follow--Up evaluations suggest, and the consequences of the BP for the various European higher education systems and universities are much more diverse than represented in these various studies. Relatively few research and policy documents taking up a more critical stance are currently available while a systematic overview of such studies is still lacking. Purpose of this paper is to provide an overview and consequently reveal the most prominent views concerning the BP, as well as emphasize the critical developments over a longer time period. A longitudinal literature review was carried out, consisting of 161 studies between 2004--2013, resulted in a final selection of 91 studies. Our paper demonstrates that the studies available in our search show that issues concerning challenges, tensions and critical viewpoints about BP exist and yet confirms that further research is called for. It is further suggested that the impact of the BP discourse would benefit from the adaptation of a continuously critical reflective approach, as an on--going part in the overall discussion about the BP.