It’s eye catching because the bright primary colors are really different from what you see in a lot of apps today! I do think the pressed bookmark button is not immediately visually apparent, so I would suggest maybe making it slightly desaturated or otherwise more obviously different from the two next to it.
Thanks for mentioning the original source! Here’s BlueScuti’s video, to save everyone else some searching. The moment he beats it is here, at 38:30.