If you have already downloaded the game and are looking for JUST the Update Patches, and none of the excess documentation or anything else, you can download that here.
This just includes patches that convert older versions of the game to newer versions, so only use it if you need to update your game for bug fixes or other additions.
If you just want the patches for the alternate modes, currently Easy Mode (Final) and Chaos Mode (Demo), you can download them here. Note that they require the latest version of The Last Promise to work correctly and are also applied differently than normal patches. (Please see the attached README.)
Also, please don't hotlink to the downloads—just link here, which will always have the latest version!
You can report issues here and download v1.3 here. But I really hope you don't have reason to do either. :P
Actually though, development has long since stopped so there aren't any intended updates for the game except for a possibly outsourced hard-mode.
On another note, if you enjoyed the game's music, you can download a collection of the game's songs in MP3 format, including original versions, remixes, and arranges of the songs (NOT the in-game versions, for the most part). It also includes some bonus songs, a list of sources (note that some songs are missing though), and a personal list of recommendations if you liked the game's music. Arranged Soundtrack Download
And lastly, if you enjoyed The Last Promise, feel free to spare me a few bucks for food/spending money! I spent lots of money and time—somewhere around 2000 hours or so—making this hack (I didn't keep track but I had weeks of all-nighters and it took place over the course of like 5-6 years, lol), so while it's free to play, I can't exactly say it was free to make. (It came at the cost my health, sanity, and other things... more than anything, I just wanted to finish it, even if the product wasn't the best I could do. That in itself was enough.)
Anyway, your support, no matter the kind or scale, is appreciated. ^_^