I installed the android app from the playstore last night.
Well, that's curious! Normally I'd just direct you to the "proper" Android thread, which is located here:
https://openxcom.org/forum/index.php/topic,2428.0.html, but would you please be so kind as to provide a link to that playstore? There's no OpenXcom in the Google Play Store as far as I know, and the version that's published anywhere but on this forum and the modsite is not known to me.
The problem is probably because of the wrong data/ruleset for the game, it's probably a really outdated version (the app has since been modified to include everything you need except for the original game data), so you should probably remove the version you got, get a recent build and try it out. Also, please PM me the .apk you got from that "playstore", I'd like to have a good look at it.