I think I have the same issue. Gauntlet electrified floor with roll up gate stage crashes on my saved game, Win 8.1 64bit. Here's the crash log:
System.NullReferenceException: Object reference not set to an instance of an object.
   at w1.b()
   at hh.a8(a7b A_0, a7b A_1, Dictionary`2 A_2)
   at aht.a(Boolean A_0)
   at aht.d6(akg A_0)
   at btt.nc(TimeSpan A_0, TimeSpan A_1)
   at bld.g(TimeSpan A_0, TimeSpan A_1)
   at a9d.a(TimeSpan A_0, TimeSpan A_1)
   at a8e.a(ace A_0)
   at atv.fv(ace A_0)
   at qi.fv(ace A_0)
   at c5.a(ace A_0)
   at ux.Update(GameTime gameTime)
   at ew.Update(GameTime gameTime)
   at Microsoft.Xna.Framework.Game.Tick()
   at Microsoft.Xna.Framework.Game.HostIdle(Object sender, EventArgs e)
   at Microsoft.Xna.Framework.GameHost.OnIdle()
   at Microsoft.Xna.Framework.WindowsGameHost.RunOneFrame()
   at Microsoft.Xna.Framework.WindowsGameHost.ApplicationIdle(Object sender, EventArgs e)
   at System.Windows.Forms.Application.ThreadContext.System.Windows.Forms.UnsafeNativeMethods.IMsoComponent.FDoIdle(Int32 grfidlef)
   at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
   at System.Windows.Forms.Application.Run(Form mainForm)
   at Microsoft.Xna.Framework.WindowsGameHost.Run()
   at Microsoft.Xna.Framework.Game.RunGame(Boolean useBlockingRun)
   at ayq.a(String[] A_0)
Saved game:
https://drive.google.com/file/d/0B9w6dsbVl-UZdDJRSGEzSDYtSms/edit?usp=sharing