Hmmmm, I meant about ummm... what kind of projection there supposed to be, like is it a platformer with sideview or from above the heads like jrpg games or isometric or is it top-down like in Hotline Miami etc? To know what kind of art you need. Then it also can be rather cartoonish or opposite, with outlines or not etc.
Also, according to story it happens kinda in real world, yeah (tomb of Genghis Khan mentioned)? But what time period? Dudes are grave robbers hmmm, have a dinamite, is it first half of XX century Indiana Jones alike situation?