UK studio ustwo has announced that its Whale Trail game has just passed 1m downloads on iOS alone, with 800k of those coming since the game switched from paid to freemium in May 2012.

“Sales pretty much bottomed out after 8 months at around 200,000 downloads and at that stage getting around 300 premium sales a day didn’t satisfy our desire to have our products seen by many,” ustwo’s co-founder Mills tells The Appside.

“Although I hate the term, we pivoted’ to freemium in the hope of increasing our user base. The monetisation strategy was secondary to the need to reach a bigger audience. We now see 5,000 downloads per day most of which come from the US which in term generates huge word of mouth and also a tidy little sum of around £250 a day which we use to drive back into the product growth.”

Mills says ustwo has been deliberately cautious when it comes to monetisation of the free version: “We could put in adverts, cross promotion deals etc and make more money but we don’t feel it would be right on iOS. It’s something we should have baked in from the start if we wanted it.”

40% of Whale Trail’s iOS downloads have come from the US – more than 410k – with China the second biggest market (146k downloads) and the UK the third (65k).

On Android, the paid Whale Trail Classic game, which costs £1.49 on the Google Play store, and its freemium version, Whale Trail Frenzy, have both been downloaded between 10k and 50k times according to Google’s stats.

ustwo is effectively sitting back and watching Whale Trail grow by word-of-mouth – Mills cites the increasing number of Instagram photos posted by fans as one sign – while also making plans to push the game and its star Willow as brands in their own right.

That includes a deal with Penguin to turn Whale Trail into digital and print books. ”They saw something special in Whale Trail regardless of it not being one of the big smash hits.. they saw charm, story, vision and love,” says Mills.

“We both feel we have a story to tell that kids and parents will absolutely resonate with. It’s not marketing for the game, it is a standalone story that we feel will form the backbone of the Whale Trail drive.”

He continues: “Anyone we have shown the e-book to has read it all the way through and been transfixed by the wonder. It’s truly something special: knowing that my kids will be proud of what we have done makes everything worthwhile. Experimenting with e-books has been a truly special experience.”

ustwo and Penguin have signed separate book and licensing deals for Whale Trail, and the studio has high hopes for other spin-offs in the future.

“We have taken the decision to push Whale Trail as a standalone part of ustwo,” says Mills.

“We and Penguin both believe in Whale Trail in many future guises, from the original game to the new Whale Trail Junior game aimed at 2-5 year-olds launching alongside the e-book, to the inevitable TV series, the film, the plush toys, the bath toys, the sweets, the candy floss, the iPhone covers, the posters, the t-shirts, to the doggy pet food. Whale Trail is a story that can and will grow.”