Is the Doom 64 Total Conversion for the PC exactly like the N64 game?
The Doom 64 TC is a great piece of work, but it is not an exact copy of the N64 original. There are several differences, ranging from minor to major, including differences in overall number and types of monsters, arrangement (playing-order) of levels, number and location of “official” secret areas on certain maps, and so on. You can get the Doom 64 TC here, and find level walkthroughs and maps here.