Over on Gamedev.net, somebody asked if it was possible to finish a game using only the time available in nights and weekends.
The answer is a qualified “Yes”.
If you are a student just learning the basics, your game may be something like “guess the number”. That is an actual game, but it is not much in terms of replay value. However, it is a project that a beginner can undertake and complete in a reasonable time, from a few hours to a few days depending on experience.
If you are a little more experienced, your game may be something like a simple Tic Tac Toe game. Again, not much, but it is certainly a game that kids love to play.
If you have enough experience and can leverage existing technologies and APIs, you can do much more in a short time.
The very popular game 2048 was created by a 19 year old over a weekend just to see if he could do it.
Cubistry was a game put together in about a month by a single programmer.
Flappy Bird was made over just a few days using existing assets an experienced developer had on hand from a cancelled project.
These games are not complex. They have simple rules, simple mechanics, and simple graphics. But they are successful games.
If you are just starting out or working alone, figure out what you can do in about an hour. That is a good work unit for a task. Now expand it out to five of those. That is a work week for someone working on their own in nights and weekends. Expand it out to ten hours of work, and that is a reasonable amount for someone to work per month.
There are a bunch of YouTube videos from Extra Credits; over the past few months they have released a series called “making your first game” that talks about many of the pitfalls of building your own games, such as how to think small, picking realistic rules sets, and launching a product.
The biggest thing is to think small. However small you are thinking, think smaller. Then reduce it some more. You may be able to only devote 30-40 hours on a project. That is about one work week every month. Then consider many major commercial projects have a few hundred thousand hours invested, plus six figures or seven figures invested in tools and technology.
You will not be making a big game. If you are imaging a major commercial game, you will not make such a thing as an individual. You cannot do that as an individual. Some of those games have hundreds of work years invested in them; working alone you could work your entire life and still not come close to finishing.
Yes, you can make a game on your own. You can make it in a month. You can even make it in a weekend. Just be prepared to scale the game down to the bare minimum definition of game. Think more like Tic Tac Toe, less like Dragon Age or World of Warcraft.
Make your game. Enjoy the process.