Why Do Protests Seem to Work In Ukraine But Not In Cameroon?

I have been significantly intrigued by how different protests in Ukraine and an African country such as Cameroon may look like. Protesters in Ukraine have been protesting against the government for about a month or so now and their demands seems to have been shifting, from entry into the European Union to state corruption. The government tried violence on the protesters but the violence did not seem to have worked and the government has been increasingly pushed to a corner by the protesters. Now we hear of warnings of civil war in the country.

If this protest were in Cameroon, for example, Paul Biya would have sent out the army to use overwhelming force to disperse the protesters. Was such overwhelming force used in the Ukraine? If it was, why did it not work? If it was not, why was it not used? Paul Biya has been in power for 31 years now but no protest against him seems to have worked. His regime has supervised massive increase in corruption in the country but people do not seem to be troubled by it. One of the issues that protesters in Ukraine are now raising is the matter of state corruption. Are people are more allergic to corruption in Ukraine than they are in Cameroon? More basic, however, is the question of why protests seem to work in a country like Ukraine but not in Cameroon or Zimbabwe or The Gambia? Do protests only work to unseat a corrupt government if there are already structures that make it possible for protests to work in a country?