Beginning game developers should naturally start out by making games that are easy to make, before moving on to the hard stuff. Unfortunately, this doesn't work out so well for the impatient. People often get into game development because of specific game ideas they have, and these ideas are usually extravagant. Developers don't want to have to wait and gain skill before tackling the games they really want to make, so sometimes they bite off more than they can chew by trying to make a very large game as their very first one. This generally leads to failure along with a shelved project that's barely even started, and can perhaps even lead to the developer giving up on game development entirely. Thus it is very important to start small and simple.There is an incredibly widespread mistaken notion that platformers are a type of game that is easy to make. This is perhaps because of the large amount of platformers for the Nintendo Entertainment System, an early console that undoubtedly changed the world. Because of the limited capabilities of the NES, it is assumed that the inner workings of its games had to be simple in order to function. This is true to an extent. But it can be said that the creators of those games were geniuses who were able to do a lot with a little. They pushed the NES to its very limits with every game. It almost seems like they didn't make platformers because they were easy, but because they were difficult. Platformers were the most complicated type of game that the NES could handle, and they were made in spite of the system's limitations, not because of them.
Platformers are complicated because of a variety of things like hit testing and collision resolution in a very large environment, as well as the necessity for inventive level design. Typical NES platformers also incorporated a range of unique enemies with unique behaviors. Beginning game developers generally don't even know where to start when tackling these problems that they never anticipated because of the illusion that platformers are easy to make. Non-programmers are even more likely to be mistaken about which types of games are hard to make and which are easy.
I would say the most difficult type of game to make would be classic real-time strategy games. When I say classic, I mean games like Warcraft and Age of Empires, not things like tower defense games which technically might be considered RTS's. I think the most difficult part of game programming is artificial intelligence, and classic RTS's have to incorporate lots of it on a grand scale, as well as things like path-finding. Platformers seem easy in comparison, yes, but there are a great many types of games that platformers are much harder than. Arcade games, puzzle games, arcade puzzle games, RPG's, shooters, and point-and-click adventures are all examples of game genres that are easier to make than platformers. If a person is looking for an easy type of game to make, I suggest one of those.
