I'm basically just linking to an article by Geoff Howland. I wouldn't normally do this, but I think it's absolutely fantastic. It's helped me no end, so I hope it'll help others as well. The link is below.

http://www.gamedev.net/reference/articles/article263.asp

It runs through the most common ways of addicting your players to your game. If you note a famous and generally well-liked game, you'll find they often manifest more than one of these at a time. The result is that it draws different kinds of people to the same game.

It talks, in brief about the following areas:

- Addiction of Finishing the Game
- Addiction of Competition (either with AI or other human players)
- Addiction of Mastery
- Addiction of Exploration
- Addiction of the High Score


There are various sub-areas to these too, which Geoff does not go into very deeply.

One thing I've found has worked for me is to have different kinds of collectables - which actually have a use.

I remember a game I worked on a while ago where you play the character of a little Bumble Bee. You start off collecting Nectar, which is used as currency for other small insects. However, as the game progresses you find yourself meeting larger animals which have no interest in Nectar - their currency is *honey*. So you have the option to convert 20 Nectar Quarts into a Honeycombe, which can then be used to bargain with larger creatures.

Then there are weapons. Your basic weapons are rocks, which can be thrown. These are handy because they can be picked up and thrown again. The downside with them is that enemies can pick them up as well (so you end up with rather amusing rock-fights where hundreds of rocks are being flung across the screen). Then you can upgrade - find a rose bush and you can break a twig off and use it as a club. You can hit enemies with it, OR throw a rock and whack it with the stick, doubling the damage. You can also deflect rocks thrown at you by whacking them out the way (that was also an example of Mastery addiction, since a certain degree of timing and aim was involved in whacking rocks).

If you find a thorny rosebush, you can pull off a thorny stick. If you hit an insect with this stick, they stick to it and weigh the end down (making your attacks carry more damage). If you manage to pin a wasp to your stick then you can also sting the enemies you whack.

Then you can collect different kinds of bag, which enable you to carry more. And different worlds to explore, where you find even more items and collectables that in turn advance the game.


Anyway, enjoy the article, hope it helps you as much as it helped me.