Question: When I see videos of the game, I see swords that are different from mine. Are there upgrades for swords and weapons in this game?

Answer: 
Yes, there are different weapons in Orcs Must Die that you can unlock either via playing the story or from purchasing the DLCs.

Also, once you unlock the [Elemental Weaver](http://orcsmustdie.wikia.com/wiki/Elemental_Weaver#Enchanted_Weapons) you can buy upgrades for your weapons during each map.
The blade-staff is the only weapon in Orcs Must Die that can appear radically different in its appearance as the model used for the weapon in-game is tied to the current character skin used. There are currently two choices the standard blade-staff can be switched to; The hammer which is available to customers who have pre-ordered Orcs Must Die and the double blade-staff which became available after the community achieved 250 million collective orc kills. Selecting a skin will automatically change the appearance of the blade-staff. The blade-staff variations still function exactly the same as each other, it's simply a reskin.

Weapons can only be upgraded in-game by purchasing upgrades from the weavers which become permanently available after level 10 (Steel & Elemental) and 19 (Knowledge). Weapons cannot be upgraded using skulls. The skulls only upgrades traps.