If you want to support SNK, consider buying Metal Slug games on Steam (the ACA Neo Geo releases), Epic Games Store, or the Metal Slug Tactics spin-off. That said, for the specific experience of the 2006 PC collection with cheats and MULTI5 menus, the hack remains the only way.
Just remember: play responsibly, support SNK when you can, and never forget to spam the grenade button while shouting “Mission Start!” Metal Slug Collection -MULTI5--PCDVD- hack pc