I absolutely loved this game as a kid. I remember spending a couple weeks straight during one summer, glued to my chair, playing this game through sleepless days and nights. The one thing that stood out to me about it was how different the focus was from most other games. It doesn't matter how many enemies you kill - the only thing that matters is accomplishing the mission as quickly as possible while preserving your men as much as possible. I thoroughly enjoy no-nonsense, mission-oriented games like this (i.e. Hitman 2: Silent Assassin, the Splinter Cell series, etc.).
With infinite sidearm ammo, you can get away with the cheap trick of luring soldiers around the corner in some of the sections. However, it's when you're limited to stealth that the game truly shines. The game becomes an intricate puzzle requiring some of the tightest timing as you eliminate and sneak past guards before they (and others) look back.
The game takes a lot of patience, and unless you've got the mission timings down by heart, quicksaves are a Godsend. If you enjoy games of this style, you may also want to check out Desperados: Wanted Dead or Alive and Robin Hood: The Legend of Sherwood.