Thanks for the information.
So you do recommend registering at least an LLC just to avoid taking a big hit if someone sues? Even if I make a game that doesn't copy anything, it's probably better safe than sorry.
If you have an income and are willing to pay the yearly filing fees, then yes. Here in Illinois, it costs me about $1000/year between LLC, attorney, accountant, Apple Developer fee, and C3 license. This does not include web hosting, artwork, equipment, advertising, software, hardware, or any other expenses. I would not be able to cover my costs on app sales alone, but with contract work I am able to pay the bills.
If I did not do contract work, there would be a 100% chance of me losing thousands of dollars because I formed a company, versus a negligible chance that someone would come after me for copyright infringement. The bottom line is that someone would have to actually care enough to sue, and there are millions of people developing things and making almost no money on sales, just like me. If you are planning to do development to support yourself full time, then yes, form a company to protect yourself. Otherwise, you run the risk of incurring lots of yearly expenses that you won't be able to recover in sales.