What's abandonment? Abandonment occurs when the mark is no longer used in commerce and there is sufficient evidence that the owner intends to discontinue use of the mark -- for example, a company stops filling orders and tells vendors that the product is discontinued. Under the Lanham Act, a mark registered with the U.S. Patent and Trademark Office is presumed abandoned if it is not used for a continuous period of three years or more.
What about similarly named games? If other games have appeared with similar names, that could be a hassle. Have any of these other game-makers already registered the mark? (Here's an explanation on how to search trademark records). If someone else registered it, it's going to be a challenge to displace the registered mark, even if you can demonstrate that you were the first user (and have "priority"). At the same time, if you seek a federal registration, it's possible that one of these other users will seek to oppose your registration, or alternatively, will fight back if you seek to stop their use. Because your course may be tricky to navigate, a trademark attorney's advice can help.