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