In storytelling, there is the concept of genre rules. Stories must establish these rules early, else the readers/audience will assume the standard ones. In the movie Arrival, when they entered the spaceship, they found the aliens capable of manipulating gravity. That’s an example of establishing the rules. Generally, SciFi will allow faster-than-light travel (warp engine), fantasy will allow mythical creatures or wizardry, romantic comedies cannot really hurt people, historical fictions need to stick to the real historical events, etc. A story that violates the genre rules feels lazy, becomes non-persuasive, and impresses much less.
That’s the Great Wall, the movie.
You can see through the shallow formulaic methodology behind the movie. Need to attract both the US and China markets, so get Matt Damon and a young attractive Chinese woman actor. This combination works for westerners, Chinese, and lady hero worshippers. Pick a good setting: the Great Wall. An action film is good for the adrenaline junkies and also gaming tie-in. Don’t add too much love scenes for censorship and rating issues. Must have fancy fighting scenes with good visual effects. That’s how the beast comes in. Need an epic ending. How about the battle in the forbidden city? That’s another good attraction to the westerners and Chinese. Excellent! Done. Gong Pao Chicken. Storyline? What storyline?
The genre rule violations are too many to cite. The great wall started around the 1st century and lasted several hundred years. The “beast”, Tao Tie, was an ancient mythical animal, known to be a descendant of Long, the Chinese dragon. If it existed, it will be 200~500BC. The “Black Powder” was invented around 12th century in the Song Dynasty. Forbidden city was built in the begging of the 14th century, way after the Great Wall.
Scientifically, the jumping without elasticity would simply killed those women. They wouldn’t be able to spear the beasts and re-jump again. The beasts’ invasion at night, that killed the big general, made no sense. If they were able to stealthily come up the wall, why wouldn’t they just kill everyone?
Wait for the movie to be free on whatever services you subscribe to. Watch on a raining day with nothing better on TV.