Is there any way that Microsoft can delete certain Xbox 360 game achievements?

Hi Marselu, I'm Luis a Xbox user just like you. Thanks for reaching out us here. Unfortunately no, no one can remove achievements even though they are not obtainable anymore

Once you have achievements they cannot be deleted. The only way to delete achievements is to create a new account and earn them again. Although if you have 0 gamerscore on certain games you have the option to delete it from your game history. Hope Xbox would
make a feature for your problem but for now you are stuck. Sorry.

To Xbox 360:

What I suggest to Xbox 360 is more deletion. I want to be able to delete achievements, game history, and download history. This would help keep my account clean. For instance, today I played Spartacus: Legends, and received a few achievements. I really don't
care for the game, and don't want that game representing me in any way. I can delete the game, but that is not good enough. I want the achievements and game history deleted, then I want to delete it from my download history as well, it bothers me being on
there.

Also, sometimes just by clicking on something on the marketplace sometimes it will download something. The other day I clicked on something and the "TODAY" app began to download, now that's on my history forever. I don't want that on there though.

Conclusion:

+Permanently Delete Game History

+Permanently Delete Achievements

+Permanently Delete Download History

You can only delete games with zero gamerscore and achievements.

To do this, open the achievement list on the Xbox 360, highlight a game with zero gamerscore and achievements and you will be able to press X to delete the listing.

Hi! For starters, have you been signed In the same profile when you completed the achievements? Have you been playing online when you completed It? Are you certain you have the latest update available for the game? Are you certain you accomplished exactly
what the achievement states In the text to obtain It? (Sometimes the fine print can be misleading.)

Next, check your saved game data, located under storage. Look for the game in question. Does the data have a yellow "!" ? If so, it's been corrupted and will need to be deleted, and sadly the achievements will need to be redone.

Have you tried clearing the system cache?
support.xbox.com/.../clear-system-cache

Have you tried deleting your profile and redownloading It? (Profile only)
support.xbox.com/.../profile-move-delete