The ability for developers to update their iPhone games and applications has been much-maligned in recent months, and often with good reason.

Games have been launched that are buggy and half-baked, with an attitude of 'release now, patch later' that's all-too familiar from the PC gaming world.

Meanwhile, other games have received updates with little value to players, purely to send them back to the top of the App Store new releases list. You could be forgiven for cursing the very idea of iPhone game updates.

Here's two reasons why you shouldn't: SlotZ Racers 1.1 and Fieldrunners 1.2 (pictured). They're two updates to iPhone games that deliver new features and gameplay enhancements, making a great reward for their existing player communities.

So, the latest update to SlotZ Racers from Freeverse has a new track manager page and scenery editing features, five new camera modes, four new cars, a stricter Championship mode, and four new bridge heights - as well as a tweak to adjust the number of mistakes made by AI drivers.

Meanwhile, Subatomic's latest update to tower defence title Fieldrunners offers two new kinds of towers - mortar and flame - along with a new game map, a new enemy, and improvements to other gameplay aspects.

In both cases, the update was about delivering new content as well as bug-fixes or performance improvements. It's a powerful reason for existing players to fire up the titles again for a new challenge.

But hang on, Freeverse and Subatomic aren't making any more money out of this, right?

The investment in new cars, towers and other content won't deliver a return, given that existing purchasers get upgrades for free. This kind of iterative development might pay off in the PC-based MMO world, where gamers are paying monthly subscriptions, but it doesn't add up on iPhone, surely?

That's not the point, though. Rewarding gamers with these kinds of updates is an increasingly important way to build not just loyalty, but word-of-mouth buzz too. Not to mention future sales if you're promoting your new iPhone games to your existing community of players.

There are still going to be plenty of unfinished games slinking guiltily onto the App Store, but what's been done with SlotZ Racer and Fieldrunners - and other titles too - shows that updates can be much more valuable than that, both to publishers and players.