Looks like gamers with Amazon Kindle tablets will no longer be competing amongst themselves... because starting today, Amazon's proprietary GameCircle platform is now open to all Android devices. The backend cloud service has offered up leader boards, achievements and progress saves to Kindle users for a year now, and as of today, it also supports conflict resolution between mobile devices. The reveal comes at an interesting time, which parallels the recent launch of Google Play game services. Naturally, it's reasonable to speculate that Amazon's move could be an attempt to keep its service relevant. More than 500 games currently support GameCircle, but for all Android users to benefit, developers must first integrate the latest API into their games. At least they now have a bit of motivation to do just that.