I got this for a birthday present. Went into the training camp and even on the lower levels I was struggling to shoot enough targets well enough to pass the qualification. (I'm not a great shooter with a controller) So at that point I figured this game was a waste of money. Figured I would give the actual mission a try, so I set it to "cadet" (remember, sucky controller skills). The actual missions were easier for me than the practice range. Each time I played a level it started me at the same spot, but there were probably 3-4 different directions I could go to start engaging the enemy and work my way to the target, and multiple directions, including high and low routes through out the game. Not sure I could do a whole level the same way twice if I tried. I think it has good replayability, because I could go at it from different angles. There are 4 difficulty levels. It is very doable, with a little effort, on level 1, even with my limited controller finesse. I have no doubt levels 2-4 would provide a good challenge for anyone. The AI seems pretty good. (keep in mind, difficulty 1) The enemy seems fairly realistic to noticing something if I'm in their view and not in cover. Thankfully if I duck out of sight, a lot of times they will just say "I thought I saw something" and go back to their pattern. There is a lot of cover to work with to keep from being spotted, which will probably be very important in higher difficulties. There are also things like planes overhead, boats, church bells, etc. that make noise and if you can time your shots with them, they mask the gun shot and they aren't alerted. One thing that disappoints a tiny bit is there are places you can't go. There are times where I thought I should be able to jump up there/across this, and I couldn't. That said, most games have some places that I wonder why can't I go there. Each mission also has a lot of items to pick up (letters, orders, etc.) and several challenges, like eliminate all enemies, spend less than X minutes in combat (be way stealthier than me). So there are other goals to attempt to achieve, beside just the main objectives.