Geralt_of_Rivia: On top of that: It looks like the slugs are generated from the product name by removing characters other than letters, replacing spaces with underscores and lowercasing the result.
You wish ....
The most impressive one:
"Dark Forces : Jedi Knight": "star_wars_republic_commando_copy3"
Republic Commando???
Also:
"Jedi Knight: Mysteries of the Sith": "star_wars_jedi_knight_dark_forces_ii_copy3"
"SNK 40th Anniversary Collection": "snk_40th_anniversary_collection_copy3".
Then there's "act_of_war_high_treason_copy3" and "downfall_redux_copy3".
Funny enough they all end with "copy3", never with "copy2".
Sam & Max S1 classic: sam_max_save_the_world
Sam & Max S1 remake: sam_max_save_the_world_remastered
Sam & Max S2 classic: sam_max_beyond_time_and_space_2008_original_version
Sam & Max S2 remake: sam_max_beyond_time_and_space
Also many slugs contain extensions like "_game" or "_base"
In many cases there's a leading "the_", in other cases it follows at the end, and sometimes it's missing completely.
No, I think that slugs are generated manually, maybe by copy/pasting the titles into a converter, but it's definitly done manually. These are human mistakes.
A manual DB fixer might be useful that only updates all IDs and slugs and optionally in a quick&dirty step looks for double slug entries and only updates these.
When the user inputs a slug to update or download one single game, go the traditional way to determine the ID from the DB. But then check if the slug provided online is different has changed and proceed with the changed one.