if these things are shadow demons, get flashlights and flash-bang grenades, it should kill them faster, also for a similar game idea but it's tower defense,protect the tree from demons by using the money to purchase upgrades and reinforcements place the reindeer on the map they still stay, purchase elves and set a patrol from point a to point b unless a monster walks in range in which case they attack, same with giant elves you can still move and attack like normal throughout the map though.
item ideas (will continue ideas with ~ key):acid (eats through all except glass items and walls),tubes (transports items), multi screening (a use for tubes: transporting items to other screens without removing completely)
 "SOPA/PIPA"){kind=icon}
 "Ultimate Santa Battle"){kind=icon}
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 "Dynamic Systems"){kind=icon}
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 "Pillage the Village"){kind=icon}
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 "Seven Deadly Sins"){kind=icon}
 "ninja physics"){kind=icon}