You've managed to incorporate shaded details with flat details smoothly. The font syncs with the overall tone. One possible crit is the skull on the lower right. The highlights on it draws the eyes a lot and seems out of place compared to the surrounding objects around the main characters. However, the skull helps complete a triangle path for the eyes, so removing the highlights might impact negatively. It might be worth trying it out to see if it improves the composition.
dude, im pretty sure that pink thing in the lower right corner is a squiddle