Check out the great enhancement patch for the original Splinter Cell

Where bigger developers like Ubisoft don't fix up their old games - the community provides, check out EnhancedSC for the original Tom Clancy's Splinter Cell.

Tom Clancy's Splinter Cell is a classic from 2002 but the PC release has a lot of issues on modern platforms, but the open source (MIT license) EnhancedSC project fixes a lot of bugs and tweaks some gameplay elements to make them smoother. It also gives you a whole bunch of extra options you can use to make the experience your own, like a one-click way to unlock all levels if you want to mess around.

On January 13th, a big update for the patch was released fixing up even more issues and further enhancing the game. Version 1.4a includes:

Gameplay

• Added an option to quickly view Data Sticks and Satchels.
• Added an option to change crosshair styles for the SC-20K and SC Pistol:
  • Beta
  • PlayStation 2
  • Chaos Theory
  • PlayStation 3
• Increased Elite difficulty starting health to 100 HP from 66 HP.
• Sam now tilts his head downward when speaking with seated NPCs.
• Fixed a bug where door interaction and Shadow Distance options were not correctly restored when loading a save.
• Fixed a bug where Sam could use a Medical Kit while dead, causing a crash.
• Fixed a bug where switching between Night Vision and Thermal Vision while using a Sticky Camera did not play the goggle switch sound.
• Fixed a bug where scroll wheel input was not cleared when entering the Binoculars, Laser Mic, or Sticky Camera, causing unintended zoom.
• Fixed a bug where the crouch-spam filter prevented crouching at the start of a level until the cooldown expired.
• Fixed Sticky Camera and Diversion Camera button prompts for controller.
• Fixed a Communication Box issue where scrolling text would jerk up and down.
• NPCs will now continue firing during Mission Failed.
• The Quick Inventory now closes if opened when the player dies.

Input

• Added full controller support in PC menus, replacing the Xbox pause menu.

Miscellaneous

• Added an option to disable the alert sound that plays before stress and combat music transitions.
• Added tooltips for Elite difficulty and Permadeath Mode.
• Increased the resolution of Sam's Thermal Vision textures.
• DSOAL is included to optionally restore EAX support. EAX can be enabled by running the eax_restore.reg script in the System folder and enabling it in-game.
• Fixed a bug where suit selection was not properly saved.
• Fixed a bug where changing the level unlock state while in-game did not refresh the level list.
• Fixed a bug where Shadow Distance always defaulted to 4x when starting a level.
• Fixed a bug where the PC version did not reset the inactivity timer when receiving input in menus.
• Fixed a typo where 5.7mm ammo was incorrectly referred to as 5.72mm.
• Fixed a localization issue where Italian text was missing accented characters.

Maps

• Training
  • Added the Optic Cable to the starting inventory.
  • Overhauled training popups to correctly reflect the player's current keybinds, crouch-drop and the New Door Interaction System.
  • Fixed missing controller training popups for non-English languages.
  • Fixed the position of a laptop.
• Police Station
  • Fixed a bug where certain areas applied excessive Thermal Vision heat radius.
• Severonickel
  • Added an objective opportunity message when failing the mission by eliminating a required target.
• Nuclear Power Plant
  • Added an objective opportunity message when failing the mission by eliminating a required target.

For a list of everything the patch does there's a full page you can check out.

The developer even put up instructions for Linux / Steam Deck which is nice to see. And testing it out personally, it worked without issues with Proton 10.

Check it out on the GitHub page.