Talking at the Go Go Games mobile conference in Gateshead, UK, Mark Rein, Epic Games' veep, revealed some figures about Infinity Blade, the iOS title developed by Epic-owned Chair Entertainment.

In terms of revenue, 33.5 percent of Infinity Blade's total sales has been generated from the in-app purchase of gold packs for $1, $5, $20 and $50.

This was introduced into the game in an update two weeks after its launch.

Amazingly, since IAP was introduced, 43.7 percent of revenue has been generated by this method, and this is despite Infinity Blade's $5.99 price.

This is comparable with Rovio's claim for Angry Birds that, since it was introduced, 40 percent of new users have bought its 99c Mighty Eagle IAP.

Size of a large cow

Of course, what that total sum generated by Infinity Blade is wasn't disclosed. However we know the game had done at least 600,000 sales at the start of 2011, which was just over a week after IAP was introduced, generating Epic/Chair over $2.5 million in up front sales. 

Hence, taking this number as total revenue - obviously an underestimate - Epic/Chair would have made around $1.25 million from IAP.

More likely however, in reality, both figures are doubled, which - if true - would give a revenue total of over $7.5 million, of which $2.5 million would have come from IAP.

New way to play

Numbers aside, Epic/Chair has clearly been surprised at the level of enthusiasm players have shown for IAP, particularly at the top $50 option.

"We won't make the mistake of not having IAP at a game launch again," Rein confessed, pointing out the difference between the 33.5 percent IAP total and 43.7 percent since its introduction as two weeks of lost revenue.

"It was a learning experience," he explained. "We haven't even leverage it [the IAP customisation options] with social features so you can show off your character to your friends. We think we could do better with this in future."

More significantly, understanding how IAP works means that Epic/Chair's future games could be more flexibility priced.

"We see IAP as a way of selling more games for less and widening our audience," Rein pondered.