Without creating a large group of events customized to each project, there's no way that I know of to take a snapshot of all the current global variables and their values (same with an instance and its variables). The easiest way to compare global vars in two different game states would be to do it one at a time in debug mode and try to hunt down any differences (but debug mode is often sluggish enough that it's not worth the trouble to try to navigate).
Is it even possible to have some sort of behavior or plug-in that allows one to use the condition "for each global/instance variable" to immediately capture all variables and their values, then store that data (in a dictionary, an array, or in a text file or something).