After a few successful tries and prompt help from moderator joachimt, I managed to successfully import my criticker ratings to icm using the following process:
1 - Export criticker ratings in CSV format
2 - Convert the CSV file to the format generated by IMDb Export (sample lines below, not every column value is needed for every line).
3 - Import using IMDB import tool in ICM, making sure you do not change the default values of the dislike/favorite options.
Have fun, and enjoy ICM and movies,
Sample lines of converted csv file:
Const,Your Rating,Date Rated,Title,URL,Title Type,IMDb Rating,Runtime (mins), Year,Genres,Num Votes,Release Date,Directors,
tt0356721,10,2020-01-08,I Heart Huckabees,https://www.imdb.com/title/tt0356721/,movie,7,60,2004,,,,,