Some features of the Amiga that are peculiar even today:

1. The mouse is a hardware sprite and its movement stays responsive and smooth even under heavy load and even when the OS freezes

2. A screen can be divided into multiple resolutions, e.g. you can have a half a screen in high res and half in low res and with double the amount of simultaneous colors (or even HAM mode)

3. It can genlock natively, i.e. match its screen refresh rate with an inbound video signal, making it popular with broadcasting studios up to the late Nineties

> 1. The mouse is a hardware sprite and its movement stays responsive and smooth even under heavy load and even when the OS freezes

Tbf that's also how it works in modern operating systems. The mouse cursor is a hardware overlay (e.g. a more powerful 'sprite') which is rendered independently from the rest of the screen (without this the mouse cursor would have a very obvious lag, as can be observed in some games that use a 'software mouse cursor').

Also theoretically at least, Windows has a feature where it bumps the thread/process priority of the application that owns the active window to make interaction feel more responsive, but this seems to get lost in the overall complexity, e.g. with some touchpads it's not uncommon that the mouse cursor gets completely stuck under high load. AmigaOS had such a 'bump active application priority' too, but unlike on Windows this feature actually worked.

What made the Amiga mouse so extremely responsive is that the mouse movement code was (more or less) directly reading the hardware registers from inside an interrupt instead of having to go through tons of abstraction layers and an event system like on modern operating systems.

> 2. A screen can be divided into multiple resolutions

AFAIK this has also 'kinda sorta' survived as GPU hardware overlays. It's just hardly used in operating systems except for video playback (and mouse cursors). The special sauce of the Amiga was that the operating system actually made use of low-level hardware features instead of using those features only in games.

> The mouse is a hardware sprite and its movement stays responsive and smooth even under heavy load and even when the OS freezes

Modern macbooks do something really interesting when the OS freezes. If the OS OOMs or something like a kernel panic happens, the trackpad stops clicking! There's something in the trackpad hardware that polls the OS and locks the trackpad when the OS stops responding so that it can't be pressed down to click anymore. Almost makes the OS feel like a real physical thing when this happens.

Implementing mouse cursors as a hardware sprite isn’t that uncommon for 2D accelerated graphics, albeit later than on the Amiga. Something like an ATI Mach32 has one for example. About 15 years ago I had a crappy Dell whose Radeon card would randomly glitch the cursor, so it survived at least until then in newer systems. The extra responsiveness is more of an Amiga thing though.