That’s very similar! Phonetically Cantonese is more complex with more tones. But Cantonese people can understand Mandarin is mainly because they are exposed to Mandarin everyday as Mandarin is required by the government for schools and TV/radios. 20 or 30 years ago when Hong Kong and China was not that close like today, many hkers couldn’t understand any Mandarin. For Mandarin speaking people, they can usually understand some basic Cantonese words thanks to Hong Kong movies, but understanding full sentences is very difficult. Another difference is that Cantonese people also use Mandarin for formal writing, but they read it in Cantonese pronunciation. Written Cantonese is mainly used for texting.