Watched everything and still in awe.
I love Playtonic's intro logo set in space -- it's just so pleasing, the aesthetic and twinkling sound. Magical.
Edit: I have a hunch this atom collectible is the Mumbo token equivalent for transformations: https://youtu.be/e6mGf50RYYk?t=2m31s
Edit 2: Tribalstack Tropics level entrance? Lick the metal balls to turn into Metal Yooka (allowing you to pass strong winds unaffected): https://youtu.be/e1gxLvbX3Ow?t=53s
Gavin mentions in the Playstation interview you can go heavy, sticky and luminous. We've seen heavy but haven't see the other 2 yet.
Edit 3: Stealth mode (uses up power meter, keeps you invisible): https://youtu.be/e1gxLvbX3Ow?t=58s
I think these multi-coloured paint cans may be for stealth mode: https://youtu.be/e1gxLvbX3Ow?t=1m28s
You can see another one of these paint cans in the corner at the top of this ramp: https://youtu.be/e1gxLvbX3Ow?t=18s
Edit 4: Fire mode breathes fire, ice mode shoots ice bullets. Water mode presumably shoots water (no footage of water mode).
Presumable Water Berries to the right of the quills here (eat them to activate water mode/ice mode maybe): https://youtu.be/e1gxLvbX3Ow?t=1m7s
Ice Berries briefly seen to the left in foreground: https://youtu.be/A99-IYExCHA?t=5m21s
Edit 5: Clara the skeleton is seen in a cauldron in Tribalstack Tropics as well as the Glacier world. I presume this means she is no longer on a spit roast at all as seen in her concept art, but does confirm she needs rescuing in multiple (or all) worlds.
Edit 6: https://youtu.be/A99-IYExCHA?t=4m49s
(These are presumably Rextro's arcade tokens... look how many there are!)
Edit 7: Two small points of interest. 1. Some caged characters can be seen briefly around Tribalstack Tropics indicating some sort of rescue. 2. The snowman character seen in the recent screenshots can also be seen in the background of the igloo area with Clara the skeleton indicating there is more than one snowman (or he moves).