Learn Turkish: Kimisi rolü harika canlandırıyor, kimisi unutuyor. - Some portray the role wonderfully, some forget it.

Both kimisi and bazıları mean "some" or "some of them." Kimisi is formed from the pronoun kimi (some) plus the 3rd person possessive suffix -si, which emphasizes "some of a specific group" (like the actors in a play). It is very natural to use the paired structure kimisi..., kimisi... (some do this, some do that) to contrast different people within that group.

Why is the accusative suffix on rol written as -ü (rolü) instead of -u (rolu) despite the back vowel "o"?

Rol is a loanword (from French) that ends in a palatalized or "soft" 'l' sound. In Turkish, certain loanwords ending in 'l' or 't' take front-vowel suffixes even if their final vowel is a back vowel. You have likely seen this exception before with words like saat (saati) or gol (golü).

How does the word canlandırıyor literally translate to "portrays"?

It is built from the noun can (life/soul). Adding -lan creates the verb canlanmak (to come to life), and adding the causative suffix -dır creates canlandırmak (to bring to life). In a theatrical context, "bringing a role to life" is the standard way to say you are portraying, acting, or playing a part.

Why isn't there an adverbial word like şekilde after harika to make it "wonderfully"?