Criticism is allowed unless you have ambitions to work in government. Critique of the government has become actually quite common in the Russian stand up comedy scene. There are some exceptions, like you cannot show any public disrespect to the Head of the Chechen Republic Ramzan Kadyrov (you can google how people apologise to him).

Edit (forgot to mention): also, participating in anti-government protests often results in people losing their jobs or being expelled from the universities

Edit 2: also, there is an ongoing crisis with the independent media: the Russian government is trying to suffocate the independent news outlets by classifying them as foreign agents (which has pretty bad practical outcomes for the news outlet)