Generally speaking, most game mechanics are not copyright-able, not patentable. Game mechanics themselves tend to be treated as base components, as in, like a drum beat or a bass line. It’s rare cases where those are distinct, usually in context (see Vanilla Ice & Under Pressure). Because a beat or bass line can be so basic as a component, it’s considered part of the arrangement and not the composition itself. Video game mechanics can likewise be in this configuration.
For instance, summoning heroes (Nintendo loss) is a mechanic / part of the composition of that game, but the larger video game is a particular arrangement. Specific characters (pikachu) can very much be copyrighted individually, but games themselves are typically less liable for patents / copyright, and so on.
Also, for good measure, since it’s a massive benefit to the freedom of expression. Video games would be a depressing medium if people could capitalize on mechanics like patent trolls.
To be clear, some technologies used in association with video games can be patented, but that’s when a patentable technology is combined with a game, which is much less common in the medium.