There are several versions of the Ramayana, with the Valmiki Ramayana being the most well-known. Other versions include the Adhyatma Ramayana, Kamban's Ramavataram in Tamil.
While most versions depict Ravana as a demon king, in some regional versions, he is portrayed as a Brahmin with great knowledge and devotion to Shiva.
Hanuman is considered a Chiranjivi, meaning he is immortal and will live until the end of the current cosmic age. This is why Hanuman is also believed to be present in different yugas.
Lakshmana is considered to be the incarnation of Sheshnag. While Bharata and Shatrughna are believed to be the incarnation of Sudarshan-chakra and conch-shell respectively carried by Lord Vishnu.
In some versions, Hanuman doesn't recognize the ring given by Rama until he breaks it open. This reveals that Rama had inscribed his name on the ring, serving as a way for Hanuman to identify him.
In Valmiki's Ramayana, after Sita is rescued from Ravana, she undergoes the Agni Pariksha to prove her purity. In other versions Sita enters the fire willingly and emerges unscathed, emphasizing her purity.
In some versions, Rama meets Ahalya, the wife of sage Gautama, during his exile. Ahalya had been turned into stone due to a curse but is later redeemed by Rama's touch.