All right, there was a bug which is now fixed, so for the proper review:
I love it. It's more of the same game we all know and like, but still, new elements get introduced and they are wonderful additions to the formula.
No need to fuss over the details; put simply, I always liked how great the platforming feels in the game. You can jump, bounce and make various twirls, and none of the other abilities (rolling, sliding, attacking, ink pen) interrupt this flow.
I also appreciate the effects (pen swipes and collecting spirals). The cat-ripping-scenery effect was also quite nice. I think this part of W4 didn't end with anything that significant story-wise (but it's good we got to test the ink pen, at least), but since this is only the first one, it's probably fine.
I kinda forgot you have a pen at the beginning which made dealing with the ninjas quite a chore. It could help to see the controls written somewhere, at least in the comments. 'S' for jumping isn't extremely common either.
Possible problems
– I'm not sure if you can take off a hat after earning it (only replace it for something else)
– I tried the gamepad option, didn't work for me (Xbox One controller). Does it only work for certain gamepads / certain platforms?
In any case, it's a great game.