I normally study Chinese but want to learn Hiragana and katakana quickly while I’m visiting Japan. On the Android app a lot of the sounds seem to be missing which reduces the utility of using skitter - also they seem to be there on the website version. Sorry if this has been addressed before - I did a quick Google but nothing turned up.
It sounds like you’re using the older build of the Android app-- you can install the beta client which has all the audio available. Here’s a link to a post with more info: https://blog.skritter.com/2016/12/new-android-beta/
Have fun in Japan! 