Speaking as someone who knows nothing about Japanese and is unlikely to use any app to ever learn Japanese... but just as a software ui/ux dev first time in. (ie take this with a pinch of salt)

On the test screens I was expecting there to be an option to shown the answers (ie cheat mode) so I could go through and get 100% score first few times.

And use that as a kind of flash card mode to get my footing in understanding stuff.

Then move out of cheat mode and see if I learnt anything!