packrat
Im not sure if you cant be sued for compensation, if proven to be the reason for financial lost, which is often attempted.
Also if you invest in marketing in that particular game name and may be build the concept around it, that could be a financial pit to switch the name.
Megalomaniak In particular if you go to register a trademark with the name, the office should be able to inform you that there's already a trademark for the particular name and what type of entity or product it applies to.
That is not the case, if you about to register a mark in the EU, they have a disclaimer that they dont check if this name is already been taken, that's why there is plenty of campanies, focus on that topic.