Alright, here are some changes I've noticed and their implications.
1. The gun can be meter burned to shoot a bang flag. This does a lot more damage and can act as a combo extender, however, it's still a high hitting projectile so it's generally not worth it for zoning wars.
2. New parry, joybuzzer shake. Deadly if meter burned since it can act as a combo extender. Not much else to say other than I hope it works for low normals as well.
3. Low gas can looks way faster, not just the startup, but the speed in which the projectile travels. High gas can looks mediocre still IMO.
4. Super is no longer full screen, but now you can combo out of it and it looks like an effective anti-air.
5. Teeth are back and seem unchanged.
6. Trait activates on laughs now, not parries. You still speed up just like before. The first laugh gives you a small boost for 4 seconds or so, but the last one gives you a big one for a long time just like before.
7. You can run with the crowbar, and meter burning the run gives you armour apparently.
8. There is an unblockable variation of the crowbar. May be gear, may be base, who knows.
9. Crowbar may not have as much hit advantage as before. Maybe CPU's aren't cancelling early enough, but the OTG stuff may be out :/
10. The Acid Flower is GONE. This move was hugely important, very sad to see it go.
Gear abilities:
1. Present box seems to replace teeth. If it hits opponent, they seem to launch towards the Joker. Also, seems like you can modify the distance you launch them just
2. You can throw the crowbar which I assume is gear ability, but insanely enough the lag for it is dash cancellable and I saw a CPU toss it, and then immediately dash, then do the running crowbar at the opponent. Oh, if this move hits, they're stunned, so you can hit them afterwards. High start up though.
3. One gear ability seems to be the power to meter burn the crowbar hits into a popup for a full combo.
4. The old parry looks back as a joy buzzer replacement. Saw the cpu randomly swipe in the old animation for it in a match once.
Main gameplay sources (high level CPU, so he's stronger and faster than normal):
And of course, the introduction trailer: