The difficulty of learning Ancient Greek?

How difficult is ancient greek compared to Latin?
How difficult is ancient greek compared to all other languages?
What is the most difficult part of ancient greek?
What is the most easiest part of ancient greek?

Harder.

How difficult is ancient greek compared to all other languages?

Erm. Much harder than Esperanto. Easier than Sanskrit or Navajo. A bit harder than German and rather more than the Romance languages. Perhaps comparable to Arabic, though they hide their difficulties in different places.

What is the most difficult part of ancient greek?

The many verb forms, and the particles. The word order of wild (that is, non-textbook) Greek can be a surprise, but only briefly (excepting Pindar).

What is the most easiest part of ancient greek?

The alphabet.

If you have already taken Latin, nothing will be too challenging save the vocabulary: each verb has six principal parts, there are both middle and passive deponents, three voices, and four moods. Everything is just more expansive.

Expansive is an excellent word for Greek.

So the understanding and comprehension of the grammar is easy, it’s just a lot to remember (e.g. all the particles and verb forms)? Am I correct?

There is a lot to remember, but I have no idea if you’ll find the grammar easy. What is your background? That is, what languages have you studied so far?

Well, my native language is Swedish. English has always been mandatory to learn in Swedish schools, so I obviously know that language too, to some extent. I’ve taken some classes of German in compulsary school, but that knowledge is long forgotten. And that’s it.

It probably will not be easy if you have not had Latin. I do not know very much about Swedish, but, unless it is an inflective language, it may be difficult assimilating Greek grammar and syntax. I only stated that the grammar would be relatively easy for someone who was already well versed in Latin because many of the constructions are similar between the two languages.

Having taken German helped me a lot with the nouns. Granted I started learning Greek a couple months after I finished high school and the German I took there but you might find yourself remember some concepts. The verbs are just foreign.

From current experience:
The verb forms are hard, but really just need extra time spent on them.
The vocabulary can be a bit more difficult to learn than Latin as most European languages contain a good proportion of Latin derivatives or are based on Latin.
The alphabet is easy - unlike Arabic ( :cry: ).

Much harder than Esperanto. Easier than Sanskrit or Navajo. A bit harder than German and rather more than the Romance languages. Perhaps comparable to Arabic, though they hide their difficulties in different places.

Rather like studying music - all instruments have their own technical problems, but in the long run they are all as easy (or hard) for different reasons.

The results are certainly worth the effort.

I had two years of German in 1977 and 1978. It was still quite inflected then, at least the nouns were. I don’t know if that is still the case now.
If it is then that aspect of Greek will not be foreign to you.
Languages can change quite fast. I was reading a Dutch book that was written about 75 years ago and the nouns and article were inflected a lot more than they are now. Now there are only traces of the different cases left.