I've yet to differentiate the "HD" rumble from just normal rumble. It just feels like there are more degrees of being "gentle" vs "strong". Is there a hardware difference between what's in the Joycons and the standard counterweight-on-a-motor?

There are several Moons in Odyssey which, in traditional Nintendo fashion, make full use of the new system hardware by vibrating the joycons with increasing intensity as you walk around the area until you feel the strongest vibration, which is where the Moon is located.

Is that so much different than what e.g. even older Xbox 360 / PS3 controllers could do? I remember games like Tomb Raider and several others using similar haptic feedback systems.

If you have 1-2 switch, there's a game in there in which you have to guess the number of balls "in" the joycon. It's a great demo of the HD Rumble feature.

The balls game was the most stunning example of this to me; I really enjoyed the experience of playing it.

In Mario Odyssey, there's a recurring challenge where you use the rumble to find the location of a hidden object. I don't know if it's just a psychological trick based on my perception of movement correlating to stronger vibration, but it genuinely feels like as I move toward the lightly rumbling controller that it not only gets more intense but actually moves under my hand, as if the vibration had moved laterally inside the controller.

This story has a developer explaining:

https://www.polygon.com/2017/5/1/15499328/tumbleseed-hd-rumb...

The gist appears to be that the HD rumble effect allows intensity and speed to be controlled separately. Traditional rumble uses a weighted motor which shakes harder and faster as current increases. I definitely have noticed rumble effects in Mario Odyssey that feel like light, rapid trembles as well as heavy chugging thuds. There's boss fights where the sensation of the rumble actually gives you an idea of how successfully your hits are landing, and it really works. However it works, it's pretty stunning.

The HD rumble is actually precise enough that you can make sounds with it. I'm told that in mario kart 8 deluxe, if you hold up the joycon to your ear as you collect a coin, the joycon itself makes the classic mario coin sound, albeit quietly.

It basically plays audio files. I've played most of my Odyssey playtime with just the joycons by themselves, no strap or grip, which makes it more noticeable. Top 3 rumbles:

1) The "fizz" when you're swimming in a carbonated sea

2) Rumbling motorbikes in the city and elsewhere

3) The scrabbling feet of a "Jaxi"

These aren't the only things with rumble, just the ones that I thought felt most unique. I've also heard that in Mario Kart, the sound of picking up a coin is essentially played by the joycon's rumble, even when the audio is off.

The difference is comparable to the difference between a traditional vibra Motor in a phone and the Taptic Engine based vibration in iPhone 6s and later, including all the haptic feedback tricks provided by later iOS versions running on these devices

It is hard to explain, but you really do feel it in Golf Story. There is certainly a difference in a "light" rumble when hitting the ball, vs a "light" rumble when the ball is tapping along a green.