The speaker is native Dutch (male voice, again, I have not attempted to modify this), not synthetic (or if it is, I cannot detect it).
I have, as yet, detect no translational errors and honestly I don't think I've even found anything arguable.
It's strictly a vocab builder. There's the spelling test. There's a "memory" section where it shows you four pictures while saying the words for each, then it repeats one of the words and you are supposed to touch the matching picture (so no native language multiple choice aimed at teaching). There's a flashcard section. The "quiz" is back to the 4 pictures from "memory", but it shows 4 pix and then says one word you're supposed to choose. "Words" offers an English language translation -- you have four choices for what the Dutch equivalent it. "Listening" is hearing the Dutch equivalent and then picking out of 4 choices the English translation. "Meaning" is a no-sound multiple choice offer Dutch choose English.
Words, Listening, Meaning and Spelling all are offered in blocks of ten. At the end you are scored and have the opportunity to put ones you are having trouble with in the "review" list.
There are 27 categories. Animals, Building, Car and City are included in the Free version. Clothing, Color, Education, Entertainment, Family, Feelings, Food, Countries, "Greating" (ha! They mean greetings), Health, House, Body, Materials, Measures, Shopping, Directions, Nature, Numbers, People, Sports, Tools, Weather and Work are all marked "Pro" so I haven't tried any of them yet. However, I am increasingly tempted.
I'll update this review as I explore it further.