I suppose that one's easy to overlook because it was only officially available in a multicart. So Treasure Island Dizzy's page doesn't have an NES leaderboard because it already exists on Quattro Adventure's page...

I'm happy to see this game with official speedrun categories now, but I'm a little curious about some of the rules! For one thing, the NES rules mention there being two NES versions, but there were actually three. The third version only came out on NES in Europe, but it's become more relevant globally as that's the version that was chosen for release as official emulation on the Oliver Twins Collection cartridge for the Evercade handheld. I was thinking of recording a speedrun of it on Mesen last year in order to request the game here, but it may take me a while to put together a good route while I'm working on other things!

So what were the differences between the second and third NES versions? The first thing you notice is the language menu, which does hold up the title screen a little, but that should be before the "Press Start to play" moment that would start your timer. There's now a map of Keldor Town in its tunnels, but speedrunners shouldn't really need that if they've already practiced their routes. Keldor Castle lets you reenter without replaying the archery game now, but you really shouldn't need to if you know at all what you're doing...

Now, the third version also starts you with one more extra life than all the other versions, which I wasn't sure would be a big deal, but I just saw the first speedrun hosted here really depended on saving up enough extra lives from the picture puzzles to survive to the end, so that could be a helpful advantage. Furthermore, I've seen button-input cheat codes that give the player another extra life to start with in all versions of Fantastic Dizzy except the first NES version and the PC version. Should those be allowed? Other Dizzy games have rules or separate categories for such codes!

Most of the terrain and item changes were between the first and second versions--which I mean to document on TCRF eventually, but that's probably going to need its own subpage with a lot of screenshots to harvest first. The second and third NES versions have mostly identical worlds, but I did find one important change: In the second version, Dizzy's enhanced speed makes it possible to jump to the island where the Aqua-Lung is found if you start his run from the right spot on the beach, allowing you to explore underwater before playing the bubble-riding game from the ship. The third version appears to have added a little extra distance between that island and the shore, placing it just out of reach again no matter what kind of jump timing I tried. So that could definitely affect what routes are possible where it might have been beneficial to collect the Aqua-Lung early, and that might be reason enough to split out a third setting for the NES category.

Now I see you've got Amiga and CD32 as separate categories, but does either of them allow the rare AGA version on floppy disk? From the developer's comments and what I've seen of them for myself, the version on the CD32 collection is simply that AGA version with the audio muted to play its own CD tracks instead. The most important difference that version has on both floppy and CD is that it includes a menu accessible during gameplay with an option to make a saved game position anywhere to reload at any time--yes, a single in-game save-state. It doesn't persist when the game is closed, but that's still a big help to be able to save just before a risky maneuver to undo a disastrous outcome, so that really should be addressed by the rules. Personally I think allowing its use makes a stronger justification for that version to be its own category separate from the original ECS version, whether you play it on floppy or CD32.

Other thoughts I had concerned the clock speeds allowed for the various versions, since running them on 50 FPS (PAL TV) systems tended to just make them slower except for the music, but I'm not seeing those differences being separated out on other games besides sorting by Platform, so maybe it's not considered a big deal here. The MS-DOS version seems to limit the speed okay too, so you might not need to worry about a maximum number of cycles, but it also lets you turn off backgrounds and star count animations if those things would really chug on your system! I'm less sure about the various Amiga models' loading times... Apparently some let you preload both disks at once to save time later.

I also once expected this game would show up here under the name "Fantastic Dizzy" common to all the ports with the new box art that wasn't recycled from Fantasy World Dizzy for less confusion, but I guess First Installment Wins!