You could also ask "Why do people draw FanArt and why do they write FanFiction?" and I belive you would get the exact same answers =)
Two of my personal motives for deciding to make a FanGame (not yet mind you, my current project has to be finished first XD) would be A) the great love for the original and B) I see wounderfull possibilitys for story and developent.
However, I can also add a C) to the list.
The challenge factor.
I'm going to modify an argument for this now that I often apply to FanFiction.

-Making a FanGame is easier then an original because the Characters and the world allready exist.
-Making a FanGame is harder then an original because the Characters and the world allready exist.

That does make sense, I promise. Let me explain:
It is easier because you don't have to invent a world and it's rules, as well as the characters and their bonds. It is allready there and others know it. So you can work on that. Great for lazy people, eh?
No.
Because all of this allready exists you will have to take extra care that you don't make any mistakes and that the characters will not turn OOC. People pay attention and they WILL notice.
As a writer, I think this is great. If I work on a story, no matter in what form, I want it to be belivable and good from start to finish. If I can manage that with a world that is not my own, it says something about my personall skills in telling said story and staing true to the original, the characters etc. And I want to give these storys to other people so they can enjoy them as well, just like I love to find and enjoy a good one in any form.

Of course you can't expect everything Fans make to be just as great as that which it is based on. Fans are "just" Fans, not professionals. Various Age groups, social groups, living ares, intellects, skills...all this comes together. And in this huge pile, depending on teh Fandom, you'll see diffrent percentages of "total crap", "meh", "not so bad", "really good" and "Oh my god, this is awesome!"
(Then again...the same applies to the professionals to a certain degree XD)

But yeah, why do people make these? Because they are able to and they want to.
Wether or not they're good at it is a diffrent question XD

This thread is from 2008. Just saying.

Oh?
XD I did not notice, it showed up on the front page with the new posts. I couldn't remember seeing this thread before and I couldn't remember the posts in it either so I assumed it to be new and followed the previous commentors.
I apollogize then, since I know 'necroposting' is not liked in this forum.

It's not your fault, it's the guy before you, Chaotech Games . ;)

Well, I personally feel that people make fangames because they think it will be easier since they pretty much have a million concepts in their heads from just playing the game or watching the movie. Is it still necroposting if 3 others have already commented ;)

Pokemon Raptor EX was awesome. :)

Strange. I'm not sure how I even found this. Sorry for that. I didn't mean to necropost, but I felt this was a pretty important topic that ended on the wrong note.

Pokemon games seem to do quite well on the internet. A problem seems to be, that everybody wants to do the same games. I've seen every name of Pokemon games there is, plus a dozen Final Fantasy Ones (which in itself, since new characters are introduced almost every game, it's really not much of a constant series. I suppose most people do it for the races of characters.), as well as quite a few Sonic the Hedgehogs (One was absolutely stunning. Just as good as any you can find in the store), and everybody insists on trying to make a Super Smash Bros.
I've seen quite a few Mario and Mario spinoffs. Some have been great, others, not so much.

Ask yourself this; how many Pikmin, Animal Crossing, Metal Gear, even Super Mario RPG (Which I would think would be a no-brainer, being RPG Maker and all) have you seen? These have some of the largest fan bases in the world. I can't tell you how many forums I've seen begging for a Pikmin 3, or asking for Chao back in Sonic. These have been out for what, 7+ years now, and nobody has bothered. If you google those, you'll find either a bunch of hoaxes (Pikmen on Youtube, Spore Pikmin, Texture hacks for the original game, ect.) or half-put together, incomplete projects (Every single Chao game out there is Dress-up, or a Chao running around a garden. Somebody made an Animal Crossing, but not with any of the characters from the game. They just used the RTP in a fixed town and called it that.) Super Mario RPG has a single hack that recolors Mario to look like Luigi, but nobody has taken it upon themselves to go ahead and do it right.

I don't know about the legality of doing something like this, but I'm pretty sure the companies don't really mind. Just give them full credit, tell people who play it to go out and buy their real games, and don't charge any money for it.

fan games express our nostalgia and influence and are perfect places to start for budding artists of all medias.

we do it cause we are ready to try the medium out and see if we can also do it.
Makings a game that fits in with your own idea of great story telling allows you to build a base and create your style. Its very simple why people do fan works.

after awhile you expand on that base and become more then your influence, an act mimiced throughout time.

"when i left you I was but the student, but now I am the master!"

Quote:I don't know about the legality of doing something like this, but I'm pretty sure the companies don't really mind.

Tell that to Square Enix. They have a history of cease and desist orders.

Or how about Take 2 and Rockstar, who if you so much as stream playing the game enact the DCMA, despite the EULA having NOTHING to say about it.

Most companies do not enjoy this. It's the same as using Mickey Mouse to sell YOUR product.

I think they make them because they love the story and game so much that they want to express their fanlove. I think its pretty cool, especially if its taken seriously and not even up on. xD