When it comes to major differences between the original release of Pokemon Diamond and Pearl and their remakes, Brilliant Diamond and Shining Pearl, they're few and far between. One such difference is the Grand Underground, a new feature that adds areas full of wild Pokemon that you can catch while underground. However, someone has taken that new addition and brought it back in time to the old games; a Japanese romhacker by the name of Tsukimi7270 posted a video to Twitter showing off their version of the Grand Underground, in Pokemon Platinum. Much like the remakes, in the romhack, there's a lava area underground, and wild encounters with a Magcargo, Houndoom, and even Groudon. The user also has a YouTube channel, full of all sorts of other rom edits to Diamond, Pearl, and Platinum that showcase newer-gen Pokemon added, odd boundary breaks, and custom encounters.