Several bobcats have been imprisoned in small cages. You can free them, and are (eventually) rewarded for doing so. You never find out who imprisoned them, or why.
The dogs in the game do not fight each other. They will toss you around like a toy if they catch you, and this does hurt, but you cannot harm them (you can, however, distract them with other toys).
Mostly related to using the fireworks. There is an option to reduce flicker, accessible from the Options menu. This doesn't completely remove all instances of flicker from the game, but does reduce it to much more manageable levels.
There are no humans, and thus no human nudity. There are also no instances of the cartoon trope where animals who lose their fur or feathers react as if naked.
Occasionally. In particular, beware the chest that contains the final egg (only obtainable after getting all the others, so it will always be the final egg).
One boss tries to eat you, and must be beaten by feedimg it hedgehogs instead.
The true ending of the game is achieved by allowing yourself to be "eaten" by a different boss. This turns out to be more like riding a vehicle, and you can board and disembark from the boss afterwards.
Cartoony: some ghostly mouse enies, if they fail to find you, will throw their heads in the gemeral direction they were searching before they vanish. There is no gore, and when the ghost mouse is seen again its head is back in place.
Some animals seem to be trapped in hamster wheels. They are free to move their bodies but cannot leave the wheel.
Some cats are kept in small cages, and are vocally unhappy about this. They can be freed.
Your character hatches from an egg-shaped plant at the start of the game, and later a boss hatches from an egg. Neither of these resembles human childbirth in any way.
A statue of a snake signifies the entrance to an area featuring a large snake (which, with the right item, can be used to play the game "Snake" as a minigame). The snake is not inherently hostile, and can be helpful.
If you fall into water the action briefly stops, and then you reappear in a safe location, unharmed but visibly frustrated. You are never shown undwewater.
Some cats are locked in small hanging cages, and it's clear that they do not want to be there (they can be freed). It's not clear if they were actually incarcerated in the sense we typically think of it, but the game does use some imagery commonly associated with it.
One boss falls into water while trapped in a heavy hamster wheel and is never seen again. We see nothing once the boss enters the water, but the conclusion is prerty obvious.