The number of downloads it's turning over might be a mystery, but Amazon's recently launched Appstore continues to be a thorn in Android Market's side, signing up yet another big name timed exclusive.

This time, it's the Android version of PopCap's Plants vs. Zombies that's to be found first on the Amazon Appstore, hitting the marketplace two weeks before it makes the leap to Android Market.

Well trodden path

American Android owners could initially pick up the game for free for 24 hours, though its full retail price of $2.99 has now come into force.

PopCap's decision to back Amazon's platform follows that of Rovio, which sold Angry Birds Rio on the marketplace for free during the platform's launch day.

The likes of Glu and HandyGames have also been notable early backers.

In all, the Amazon Appstore plays host to a number of big hitters, such as Flight Control and Doodle Jump, with the retailer looking to bed its marketplace into the Android ecosystem by openly courting the platform's major players.

[source: TechCrunch]