With both Tizen and Android being open platforms, there is an opportunity to enable running applications of one platform on another. RIM took this approach with the BlackBerry PlayBook tablet, which can run Android apps that were recompiled for the platform.
ACL or Android Compatibility Layer by OpenMobile offers a similar solution for Tizen. It adds support for running any Android application in its unmodified state without the need for recompilation.
Unlike BlueStacks, which allows running Android applications on Windows, this is a not a software one can download on their Tizen device to make it compatible with Android. If an OEM wishes to provide support for Android, they can modify the kernel and add support for Android applications in the very core.
Android has accrued a huge collection of applications by now, and by adding support for those applications in Tizen devices out of the gate, it can have a fighting chance.
It is important to note though, that while Tizen might support Android applications, it will be rather unlikely for it to feature Google Play — the official app store for Android. On the other hand, there are alternative markets such as the Amazon store. There is also the option to directly distribute or sell the app as an apk file. Even so, this isn’t as simple a matter as getting all Android apps for Tizen immediately on launch.