What are some similarities and differences between a two party system and a multi party?

I guess the most glaring difference is that in a multiparty system, the parties are free to have their opinions and platforms come from their actual opinions, rather than having the agendas set for them based on what the other group is doing. For example, in a two-party system, if one party comes out staunchly against gun control or abortion, the other party is automatically defined by their opposite, with very few exceptions. As for similarities, I guess the best answer is that you at least have opposing points of view coming to light, as opposed to a singular party system like China wherein dissension of any kind is not tolerated.