Ok, so I forgot to post about this when it first surfaced because of life stuff, but recently, those magnificent lads in the SC modding community have made massive progress towards enhancing the PC version of SC1 and slowly turning it into the most “definitive” possible experience.
Last month they revealed that through data mining efforts, the files for the cut levels Nuclear Power Plant and Severonickel were found in the Korean and Japanese release of the Xbox version, making it possible to try and port them to PC (an ongoing WiP).
Today, they released an Enhanced SC patch which includes said levels in a somewhat playable form (still very WiP though - see my remark below), as well as numerous gameplay enhancements and level versions ported from the Xbox version, with improved lighting and mesh. QoL improvements and controller support are also included, as are ThirteenAG´s widescreen fix and dgVoodoo2 (for fixing the lighting and FPS issues).
The release info on Reddit can be found here:
https://www.reddit.com/r/Splintercell/comments/1k6zim5/enhanced_sc_a_new_major_patch_for_splinter_cell_1/
Or you can go directly to the patch´s GitHub page:
That being said, the patch is still WiP, especially where the cut levels are concerned, and the modders are looking for anyone who can help them overcome the issues, specifically anyone who is familiar with Unreal Engine 2.
Here are also the links to the original announcement from last month:
https://www.reddit.com/r/Splintercell/comments/1jdxl4j/major_development_splinter_cell_1s_cut_levels_are/
and the subsequent update, which also details some of the issues the modders are facing with the level porting, especially audio:
https://www.reddit.com/r/Splintercell/comments/1jph4x2/update_splinter_cell_cut_levels_on_pc/