Can I get a virus?

Games are very resource-intensive. They will heat up your machine. You can download all the games you want. Ideally, download them from the Mac App Store. Otherwise, make sure they have valid signatures. If your Mac refuses to open it, please don’t follow instructions to disable all of the built-in antivirus protections on your machine. People do that. Minecraft is a popular game and should be safe. If you download add-ons that did not come directly from Minecraft, then you might have to be more careful. Again, all you need to do is pay attention to security dialogs. If your Mac doesn’t want to open a file, there is probably a good reason for that. If you are playing these resource-intensive games while on battery, then they will drain your battery and reduce your battery life over time. But that is not a knock against games per se. Any software will do that if you run on battery. Don’t run on battery unless you need to.