Ok, I found another strategy that can save some fractions or even full seconds.

This one i'll name "The Smedley Crit" or "The Bear Crit".

In the 1st level bossfight, right after you hit the bear with your beak, and while it's in that damage animation, you can jump right away and beak the squirrel in the tree, so it'll drop a hazelnut on Smedley - and for some goddang reason - when the nut hits the bear while he's in a damage animation and "INVINCIBLE", he doesn't play another damage animation, thus losing his 'invencibility', so you're able to do that 4 times in a row and save god knows how many seconds.

This Level 1 TAS applies this little trick: http://dehacked.2y.net/microstorage.php/info/1696553868/teste.bk2

Note: It's humanly possible! I got it in less than 15 attempts in practice. Note 2: It's probably possible to do it in the Level 3 boss (Polar bear), but I haven't found set-ups do that, and if that were to be possible, it would probably be way harder. Note 3: Yes, i am working on a full-game TAS.

yoooooooo that's so awesome, thanks for sharing, and good luck on the tas :D