I don't know if the Lost Media folk have yet invaded the domain of danmaku STG but if and when they do, you can assure the first topic of discussion will be DoDonPachi Campaign Tokubetsu Arrange Version (aka "Blue Label", based on the altered title screen), a unique arrange of Cave's genre-defining 1997 arcade game DoDonPachi that was exclusively gifted to the winner of a score-attack content held to promote the Sega Saturn port. As far as anyone's aware, Cave only burned two ROMs, one for the winner and one for themselves; Cave made their build publicly playable at a live event in 2006, and the winner of the campaign PCB has made it playable on a couple of occasions and even allowed a doujin superplay circle to capture a 2-loop run for a VHS release back in 2003, but it apparently had some component issues the last time it was booted and hasn't been out to play in a long while. Last anyone checked, Cave's official stance is that they wanted the campaign arrange to remain the exclusive property of the campaign winner and explicitly did not want to port it, and who knows if either or both versions are still functional or accounted for, so there's a very real possibility that it might never be played or seen ever again.
There's more to Blue Label than just the allure of being a rare game: in addition to substantially revised enemy/star placement and boss behaviour, as well as palette changes and other graphical tweaks, it features an early version of the hyper system that would formally be introduced by DDPDOJ in 2003βit's essentially a road-test for the systems that would come to define the later games in the series, prototyped within DDP, and one can only imagine how transformative an experience it might be...
...or, if you're a complete sicko, you can attempt to painstakingly mod the original arcade ROM to implement all the Blue Label changes in exacting detail, as this one modder revealed they'd been doing a few weeks ago. Through poring over old interviews and obsessing over the old doujin superplay, they've identified and allegedly implemented a myriad of little tweaks, including relatively complex endeavours like upping the bullet limit; without access to the original game, it's impossible to truly verify just how accurately or thoroughly they might have recreated the authentic Blue Label, but they clearly did their homework.
A release for the full patch seemed to be imminent, but the dev just dropped an update declaring an indefinite pause on the release, due to "new information" that they can't disclose, but are hinting that the reasons may become public sooner rather than later, and that it's ultimately for the benefit of the community that they cease working on the mod. Immediately, two thought spring to mind: one, the hypocrites at EXβ±― are bullying them because they're doing something with DDP on their own platform, as they've done recently to MAME re: certain other Cave game, or two, M2 has something cooking with DDP and has asked them to refrain from releasing the patch; they apparently talked down the recent creator of a Dimahoo gadget mod (which basically repurposed the gadgets from the M2STG Mahou Daisakusen release), who also gave some vague but optimistic statement when they pulled their work, so there is some precedent for M2 being both aware of and willing to police even smaller EN-centric mods.
Personally, I think it's just a matter of time before Cave officially authorises some sort of public reissue of Blue Label: they put out the Guwange and Ketsui one-off arranges, which IKD apparently just kept in his desk drawer this whole time, and I can't imagine M2 hasn't earned enough goodwill to allow them to preserve this version as part of the inevitable DDP reissue. I also had my concerns about whether the modder and/or the broader emulation community would've done their due diligence in making it known that this is just a hack and not the genuine article, so a part of me is a little relieved it didn't just drop and cause a whole bunch of disinformation.