Thor's hammer has a short handle not like the one in this movie.
(at around 18 mins) When Odin is lying on the ground dying, Thor comes to console him. As Thor leans down, the bottom of Odin's right boot can be seen, exposing a decidedly modern hiking boot tread.
Various characters are trying to find and use the Hammer of Invulnerability. This should mean that whoever has the hammer cannot be beat. But it seems that every character who actually used the hammer got their butt kicked. So the hammer should have actually been called the Hammer of Vulnerability.