Eliminate Pro Becomes First Free App in the Top Grossing List

eliminate_proI’m not sure how many of you are playing Eliminate Pro on your iPhones, but I’m guessing it has to be a fairly high number, considering the app’s success since its recent launch. ngmoco’s ambitious first-person shooter for Apple’s (s aapl) mobile platform is third overall in the App Store’s Top Free list, but what’s more impressive is the number 22 spot it currently occupies in the Top Grossing list of apps.

That’s a huge step for the micropayments business model made possible by the introduction of in-app purchasing in iPhone OS 3.0. It marks the first real evidence that developers can make good money offering a “freemium” model on the iPhone platform, with users getting the initial product for free, but paying for in-game rewards and additional content.

ngmoco appears to have found the sweet spot in add-on content where users don’t feel like they’re being extorted by a game’s in-app purchasing system. Eliminate Pro uses a system in which players earn rewards for in-game achievements that can be used to purchase armor and weapon upgrades. The catch is that you only get a certain amount of time during which game play earns you points. You can keep playing for free, but in order to get more rewards, you have to pay for more usable time.

Users can buy blocks of active time using the in-app purchasing system, in $1, $10 and $30 dollar increments. Players seem to have taken a shine to the system, since in-app purchases alone account for all of Eliminate Pro’s gross revenue. ngmoco also has a strong community and social media promotions effort in place behind the new title.

The company’s other title that depends heavily on in-app commerce, Touch Pets Dogs, hasn’t yet mirrored the success of Eliminate Pro. It hasn’t been available in the U.S. store for quite as long as Eliminate Pro, but I suspect the fact that its target audience skews much younger has more to do with its weaker performance. Eliminate players are far more likely to be in a position to have access to a pay-capable iTunes account.

No doubt ngmoco and other developers will try to repeat the success of Eliminate with other apps based on the same model. Personally, I’d be happy to see more games along the same lines, so long as developers remember that “freemium” does not mean “artificially handicapped.” Eliminate Pro works so well because it’s fun even if you don’t make use of the in-app purchases. As a result, users feel that ngmoco is operating in good faith and are willing to spend money on enhancing their experience.