Well, the cartoon dog boy's adventures are diverse. Sometimes he's on a quest to find a lost treasure, and other times he's helping the community solve problems. There's never a dull moment for him!
In the manga, Guts' character development is explored more deeply. The anime might focus more on visual action scenes. Also, the art style can vary, with the manga having a certain grittiness that the anime might not fully replicate.
The artistic style could be something like anime, with big eyes and flowing hair for the girl. Or it might be a minimalist style, focusing on the essentials and using few elements to create an impact.
In cartoons, suspicious eyes usually feature a squint and maybe a bit of a furrowed brow. The colors used for the eyes could also be darker or more intense to convey that sense of doubt. Also, the way the character holds their head and body language can enhance the effect of the suspicious eyes.