Decent for a budget game.
When you start the game, you select all your weapons and items your are going to bring with you on yor mission. Then you select the starting point where you'll start the mission. It's obviously best to start off at the spot closest to your destination.
The missions are pretty straight forward and the whole game runs on a stealth engine. The main problem with that is that it is in first person. It is easier to see your character so you know if he/she is well hidden or not. Sometimes you'll find yourself sniping a guard but all of a sudden you'll die. The enemy intelligence is pretty high actually, but there are so few guard in the game it makes things a lot easier. Some guards will be hiding in places. Also, sometimses guards will do stupid acts like hiding standing up in front of a window where you could easily spot them.
The graphics are pretty dark and dim so I found myself using the night vision goggles frequently and I prefer not looking at eveything in green. Also there are some graphically flaws. Sometimes you'll see enemy hands and feet coming doors. I once saw an arm sticking out of a stone wall and shot it to hear a moan.
The sound is pretty realistic from the gunshots to the enemies. They sound all about the same but the voice acting is decent. The grenades sound pretty real when exploded.