what is mean"impressive on so many levels it's almost ridiculous"?

Praise. Almost ridiculous; almost unbelieveable. Almost in the sense of 'approaching but not arriving; nearly, but not quite'. I almost won (I didn't win). I almost lost (I won). I almost succeeded (I failed). I almost failed (I succeeded).

Thank you so much.Your Explain was more than enough.

Yes, his explanation was almost ridiculous.

(Ignore me Maya... I am just joking around).

I just want to know I understand correctly , ridiculous in this sentence is synonyms to unbelievable ?

Some synonyms for 'ridiculous' used this way: unbelievable, incredible, ludicrous, fantastic, impossible.

Thank you so much . I got everything I need.

You should understand that this use of word "ridiculous" is informal. Americans wouldn't use this word in a professional or formal setting. You also have to be careful since the word "ridiculous" can also be used to mean "absurdly stupid".