Learn Hardcore Turkish: Eleştirmen filmi beğendi.

Because filmi carries the accusative case marker -i, which Turkish uses to mark a definite or specific direct object (“the film”). If you omit -i, (film) it’s interpreted as an indefinite or non-specific object (“a film”).

What is the function of the -i suffix on film?

The suffix -i is the accusative case ending (one of four vowel-harmonized forms: -i/-ı/-u/-ü). It signals that film is a definite object. Without it, the object is indefinite.

How do we decide which vowel to use in the accusative suffix -i/-ı/-u/-ü?

Turkish vowel harmony dictates the choice:

After front unrounded vowels (e, i), use -i
After front rounded (ö, ü), use -ü
After back unrounded (a, ı), use -ı
After back rounded (o, u), use -u
Since film ends in i (a front unrounded vowel), we attach -i: filmi.

Why is the verb beğendi at the end of the sentence?

Turkish is a Subject-Object-Verb (SOV) language. The default word order places the verb last: Eleştirmen (S) filmi (O) beğendi (V). You can reorder for emphasis, but the verb typically stays at the end.