I found this app while looking for a way to learn Russian for a university course I'm in. It is very handy and useful, and although it is geared for children, it's great for beginners of any age.
That said, I have noticed a few small errors, like how the alphabet only has 32 letters (there are 33 in Cyrilic); the letter X ("ha") is missing. It took me a full semester to notice, however.
The sound for pajamas (?) is missing, so if it is silent, it's that one. The word for "Ladybug" (Bozh'ya Korovka) is represented by a Dragonfly (Strekoza). Some of the images have sounds associated with them (which are annoying, and can't be turned off), and some do not. Animals, for example have animal noises in most cases, which makes it harder to focus on language. Several pictures of trucks which represent very different kinds of trucks don't really stand out in your mind.
I have also used the E Flash Apps version of this app for German, and appears much more polished. Overall, it is a fun and useful app to play with/study when you have five minutes to kill. I have recommended it to my classmates, and would gladly pay for an upgraded or debugged version that had more categories and the ability to turn off sound effects.