Yes, the lack of grammar, especially for a language that's "far from your own", is something that makes a lot of people angry. If you want to learn a language only so that you can order in a restaurant on your next holiday trip or ask for directions or just as a mental exercise - then it will be enough. But if you really want to learn a language you need additional resources.

I've been learning Danish for a few weeks and they have this "what is wrong with my answer" feature, but I learnt English and French the "old-fashioned" way and would like to look up the rules of the why and the how ;)