Here are some well-coded or otherwise enjoyable or interesting demos, according to me, with a short text why they are noteworthy. There will be many omissions, because I have watched thousands of Amiga demos, and many have inspired me and will yet be missing here.
Unit A Break! cracktro
The first effect intro for which the release date is known. I never saw this back in the day; it's the result of research for my Amiga Future articles, and this effect was chosen.
BS1 cracktro
Though slow, this told me that the Amiga was much more capable than the 8-bits I knew well. This early there were no stores selling software, so cracking groups were the gateway drug. ;)
1988 A.D. by Thorax
The first demos only has sampled loops. This is one of the first demos I saw that told me that the Amiga could produce a sound quite different from 8-bits and even the glorious C64 with its distinct SID sound.
NS & FLT Megademo II
This showed me the strength of megademos, where all group members could express themselves freely. This one shined not least due to the excellent music by Titan (later known as Uncle Tom). MD 3 would get more, and some inspiring gfx.
Megaforce Megademo
I kept in touch with everyone, and also kept in touch with foreign contacts thanks to my swapper. Megaforce had been busy and built a great reputation, to great to be ignored at the time, and not least the gfx and music showed what perfection could be like. Same for W.O.W. and D.O.C. and many others.
Sounds of Gnome
This musicdisk has great freedom in thought, which Mahoney would go on to express, coming from C64 to Amiga. I was still learning as he was, but I put in a ton of work at this party and it resulted in my first compo release, leaving B.R.A.I.N.S. for I.C.E. (or Empire). What's with these dots, anyway. I guess they were popular. :D
Phenomena Megademo
4042's part and generally being in touch with the Swedish scene inspired me to join Phenomena, and this was when I dedicated all my time to helping the group in any way I could, with code, music, and gfx, putting my graduation in grave jeopardy(!)
I got to know all the members, and of course Firefox and Uno.
This was perhaps my most productive time ever, with vector inspiration from IT and CRB (Norway), and Glenz from Celebrandil/FLT's Animotion and Promax/Kefrens's parts on Megademo 8.
There were also many Megademos with varied parts worthy of mention, including those from the aforementioned Kefrens, Cryptoburners, Red Sector, Dexion, Crionics, Rebels, and many more.
But things took a turn. Someone was about to release the first trackmo.
Mental Hangover
This was equal to a 3-person Megademo, and quite different. Rather than watching a production for a favorite part, you would now watch it continuously scripted or at least linked, enjoying it to the end, hopefully from a fairly high quality throughout.
This was not always the case with Megademos, whose entire point was having everyone expressing what they liked (heavy metal/fantasy-inspired and synth/cyberpunk-inspired parts on Kefrens megademos being a great example!)
Slayer had not quite impressed previously with Seven Sins, I could already do better due to all the intensive work I put in for Phenomena.
But here was a new idea, with this sort of stylish gfx by Reward that Uno thought was genius, certainly competent code, and kind of crazy "I don't give a shit" kickass music by my friend Uncle Tom. He had made great compositions in all styles as we know already, now he wanted to rock - and he did.
And the combination inspired the (unreleased) Stunner trackmo, other trackmos, and one-file and multipart demos since.
One-file demos worthy of mention include those from IT, Aurora, Delta from Red Sector, and many more, such as this absolute gem.
Natural Movement by Tristan Lorach
This demo showcases a 3D engine that consists almost exclusively of calculations. The camera is dynamic, animations are interpolated and feature weighted joints, and not only can the camera follow objects, the objects themselves can follow other objects. An entrancing release.

When the Demoscene chose paths

One trackmo can never be forgotten. It forced a choice regarding what you like to see in a demo. In the demo competition at The Party in Denmark, two releases fought for first place, and the demo with new effects placed second.
Hardwired by Crionics & The Silents
This was the watershed demo that was lauded by many, perhaps by coders the most, so that it inspired many following demos for its story and flow, with many new and technically excellent effects, representing many hours of coding work as well structural and design work.
This was when I first saw the thumbnails of effects in an end scroller. Today we just screenshot it in an emulator and convert back to Amiga, but depending on the effect this could be quite difficult to do if the effect contained sprites or used non-linear bitplane pointers or Copper effects on top.


Slayer would go on to make a few quite interesting scrollers, and then promptly leave the Demoscene. Now, don't get me started on scrollers, or my list of gems would be endless, cos I love them and nobody else appreciates them apparently. :'(


Obviously I've released quite a few scrollers, but this space is reserved for lauding others. I will mention a couple, all right?! :)
Easy Ruling
Inspired so many inventive variants even I cannot keep count. The similar ones are more obvious than the twisters, spinners, zoom/perspective scroller thingies and chunky modes that are a proper way of making the Copper sing and dance. :)
Dexion Megademo 2 Star Wars scroller
Here's a one-off that displays a stroke of genius, an actual mega mind at work, with full knowledge of the Amiga hardware. It's actually unbeatable - all of the subsequent entries were just scanline effects - they just didn't get it.
Speaking of scanline effects,...
Total Triple Trouble
Before twisters, before slimy cubes and most "car game roads" effects, there was this fresh experiment by Rebels, which draws its power from an entrancing soundtrack coupled with focusing on variants of the effect. There is also a precursor of chunky here, likely inspired by the hand scanners and matrix printers of the day. At least I was, and wrote multipass printer routines to render grayscale onto 'canvas'. :)
Silents also returned with more scroller types, such as this one:
Tropical Sunset
..which strange as it may sound, is likely to have inspired a Blitter zoomrot of sorts.
... to be continued with more scrollers, the Golden Age of 40K and the second Golden Age of AGA/030 demos ...