Translation:I drink alcohol every night.
It might work as a free translation, but Duolingo wants you to translate as closely as possible while still making sense/sounding normal, so it's best to include the alcohol so it knows you know what おさけ means. のみます also doesn't imply alcohol more than any other drink when left on its own as far as I know.
Apparently Japanese has something called a "pitch accent", which is like a tonal language like Chinese in that each syllable (well, mora, in the case of Japanese) has a specific tone you have to say, and which really has to be memorized for each word. Though what sets this pitch accent thing apart from fully tonal languages is that tone is a property of the word, rather than the syllable. So for a string of N moras, there are N+1 possible tonal patterns. https://en.wikipedia.org/wiki/Japanese_pitch_accent
Agree ばん is evening and night I believe. Also おさけis a specific drink as well as alcohol so both sake and alcohol should be correct. There seems to be a common inconsistency of required specifics for words like this in these exercises (some words you need to give the specific word rather than general to be correct and vice versa)
drink and drink alcohol "technically" are the same thing, as one implies the other. I don't know of any case where one would say, "I drink a lot" if it was the case where you drink a lot of water, unless it was in the context of that liquid. And even then alcohol jokes would ensue.
I think, "I drink every night" should also be accepted as an answer.
Unless I missed something and お酒 should mean only rice wine and not other types of alcohol. It is used on the drug stores/ convenience stores signs. So in the same way that one does not need to differentiate rice wine from vodka when reading 酒 in Japanese, one does not need to differentiate "I drink every night" from "I drink alcohol every night". And does anyone actually say that? Are we asking that everyone just literally translate? Or convey meaning?