Ronaldo signed a 2-1/2 year contract estimated by media to be worth more than 200 million euros with Al-Nassr, making his debut in January.
He scored 14 goals in 16 games but it was not enough to help his side win the Saudi Pro League (SPL) title, with Al-Nassr finishing second behind Al-Ittihad.
The Portuguese, who missed the final matchday due to injury, said the league was very competitive but that there were many opportunities to grow.
"We have very good teams, very good Arab players, but the infrastructure - they need to improve a little bit more. Even the referees, the VAR system, should be a little quicker," he said in an SPL interview.
"But I'm happy here, I want to continue here, I will continue here."
Ronaldo said he had adapted to life at the club, though there were many differences from his time at Europe where he played for elite teams such as Manchester United, Juventus and Real Madrid.
"In Europe we train more in the morning and here we train in the afternoon, or night. When you start Ramadan, we train at 10 o'clock in the night. It was so strange," he added.
Since Ronaldo's arrival, several other top players have been linked with a move to the Saudi league, with Lionel Messi receiving a formal offer to join Al-Hilal next season.
Ronaldo's former teammate and Ballon d'Or winner Karim Benzema has reportedly received an offer worth more than 100 million euros from Al Ittihad.
"If they are coming, big players and big names, young players, 'old players', they are very welcome," said Ronaldo.
"If that happens, the league will improve a little bit. Age is not important."
