Follow the Leader: The game doesn't even try hiding its inspirations from the old-school Tomb Raider games. Some may even argue that The Infernal Machine is a better follow-up to Tomb Raider III than The Last Revelation, which came out virtually at the same time.
Keep Circulating the Tapes: Said microcode poses a problem today; N64 emulators generally rely on emulating the microcode, instead of the hardware directly, in order to get playable framerates on even high-end systems. That trick doesn't work when the developer throws out the standard libraries from the SDK and rolls their own microcode. Headway has been made in emulating the RSP directly and enabling custom microcode, and indeed some emulators finally can actually boot the game, but currently the only way to actually play is to find a real cart note or shell out big money for a flashcart and drop it into a real console.
What Could Have Been: The game was originally to have been one level longer, with an additional level between Tian Shan River and Shambala Sanctuary called Shambala Waterworks. In the end, the waterworks were merged into a small part of Shambala Sanctuary.