So, now for the part where I explain what I had to do. I downloaded a program called dgVoodoo and copied the DirectX dlls from the MS folder into the game's install folder (UbiSoft/Ed/). The fancy effects like anialising can be activated in the dgVoodoo control panel. Remember to add the install folder first, overwise you'll just be editing the default config file.
Before starting the game, you should take a look at the setup program to set up the graphics settings. I've never had any luck with any resolution other than 800x600 with this game, but it seems I can get dgVoodoo to get it to run in 720p and even 1080p.
As for the OEM patch, a Google search for the filename (tt_castlepatch.exe) brought me to a UbiSoft support page where I found out they still host the file. after letting that extract itself, open the program it placed in the game data folder (Ubisoft/Ed/GameData). There's also a 3D sound card patch you can get off of The Patch Scrolls. You just need to place the files in the game's dll folder (Ubisoft/Ed/dll).
While I don't know if it helped, I also followed a post that said that they also turn on compatibility mode (Windows XP SP3) for all of the programs in the game folder (Ubisoft/Ed) and the disc itself. Also, the game will need to run in administrator mode. To be fair, this is from that era where security was a lot more relaxed on PCs.