The premise of "Welcome To Marwen" revolves around a revenge plot reenacted by tiny toy soldiers. A soldier left ravage by PTSD, stands decimated by the atrocities committed by Nazi occupants in his hometown. Of course all of that occurs in a transliterative universe. The titular character channels his energy into building and painting a WWII doll village called Marwen, which he somehow brings to life. The soldier played by Steve Carell, then instructs the dolls to take up arms against his "fictional" attackers.
It's hard to pinpoint whether the embellished story is done in good taste, but Carell plays a real life survivor of Nazi warfare named Mark Hogancamp, a man who defended himself after being attacked in a bar in the year 2000 for being a cross-dresser. The transmutation of themes present in both the WWII narrative and the real life injuries suffered by Mark Hogancamp, come together to tell a singular story of retribution. The real life Hogancamp resorted to to creating a house of Dolls after being attacked by people in his village.
Robert Zemeckis, who directed Forest Gump and Cast Away, obviously saw enough in the script to jump at the chance. If the plot makes little to no sense, maybe the trailer will help situate you?
But maybe not?