There is no dedicated jump key in IGI 1. Pressing Spacebar (or your default action key) makes your character vault over low obstacles like sandbags, crates, and low walls, but you cannot perform a free-standing jump.
Since contextual jumping is rare, memorizing the maps is key. Here are the most common places the "jump" works: how to jump in igi 1
Since IGI 1 was designed for older Windows versions, it may experience input lag or glitches. Setting the game to run in Windows XP Service Pack 3 compatibility mode through the IGI.exe properties can resolve movement unresponsiveness. There is no dedicated jump key in IGI 1
If you can’t jump over something, try these tactics instead: Here are the most common places the "jump"
Locate the fence, crate, or ledge you wish to traverse.
If an obstacle is waist-high or higher and not a sandbag or specific low wall, do not waste your time trying to jump it. You must find a path around it.
Now go complete Mission 4 without falling off the bridge. Good luck, operative.