Sometimes a limited palette can be really useful. It may look 'colorful', but it's really just... green. Open it in PS and look, more or less one shade. The variation that makes him live is saturation.

This is a paintover of one of my students painting.

Ship

Sea battle

White knight

Halo

Knight

Diplomacy

Ship

Hovership Hall

Lord of the Rings The Gates of Argonath

HORIZON: ZERO DAWN

Dragon

AC

SUBWAY

Bridge

Landing

Rapunzel - concept art for Disney's Tangled

AC

Rapture