Ayyy thanks for playing!
Yes, cancelling wall-grab into jump is intended and even required if you're doing low item% runs! You can also scale walls infinitely by doing so. The game is meant to allow you to win with 0% items (read: only your hook) if you choose to, even, there's a lot of strats & techniques for different parts of the game.
My pixel art arc was actually fairly recent, I had been doing high-res art assets for a long time but felt like I would often obsess with details too much, so I tried pixel art to test myself a bit by simplifying things, taking a "less is more" approach, ya know?
Glad you had fun!