Good but should be improved
Thank you for developing this app! It’s great, overall. However, I think the vocabulary list of each topic is a bit short. It should be longer. Besides, I guess the underlying idea behind those lists is to use words actively, not just understanding their meaning solely. Therefore, the app’s exercises should focus on that, as the word lists are pretty much familiar to IELTS learners. Also, it would be better if the example sentences are relevant or closely related to IELTS activities. Another thing is that since most words are familiar to learners, some people might overlook the app’s meaning. However, we are not sure know how use them appropriately in the right context (formal or informal?, speaking or writing?). Therefore, it is better to emphasize the notion of ‘active’ and ‘passive’ language for the sake of the app’s popularity.