(Native Spanish speaker here.)

First: This app is amazing!

But I think that this app is doing almost a word by word translations, without a list of usual expressions or grammatical analysis.

For example, the correct translation of 'Dead End' is 'callejón sin salida', that means literally something like 'street without exit'. Translating word by word 'Dead End' you obtain 'Muerto Fin' that is unintelligible.

Another example from the video is the translation of

  'Lengua boliviana con una salsa picante de anchoas'.

The app translates this as

  'Tongue Bolivian with a sauce spicy of anchovies',

But the correct translations is something like

  'Bolivian Tongue with a spicy sauce of anchovies',

because in a translation between English and Spanish you must reverse the order of the adjectives and nouns.