I was playing a game that was installed on my external.. After quitting the game I couldn't open the HDD. Here how it looks.

Whenever I try to open it, I get a message saying something like "file or directory is corrupted and unreadable"
Please if anyone experienced this kind of problem before, and you guys know the fix, let me know. Thank you.
(I would like to keep all the data on the HDD, in other words I dont want to format it)