It's +2 more than it should be.
eg loading a .com file, initial sp should be 0fffe, but it's 0000.
For MZ files, like the Symbology demo, it's 0102h instead of 0100h (which actually causes a crash later if you single-step at any point).
Interestingly, the initial zero is pushed to the stack as it should be.
This might be a reason why some demos don't run, though Symbology's problem is keyboard-related.

The initial sp is also wrong when debug.exe is run with no parameters (00fdh instead of 0ffeeh).