Walkthroughs for the stuck. :)
Level 1: Do as the game says, just go through it
Level 2: Go up to the corner on the wall, tap the wall, then break the guy's neck as he comes over.
Level 3: Same as level 2, except this level's shaped different.
Level 4: Open the door, but don't go through. Tap the wall right next to the door and break the guard's neck as he comes through. Lockers: Top contains 5 C4, third from top contains a keycard, and the bottom one contains garbage. XD
Level 5: Push the box on the pad.
Level 6: Shimmy along the wall upwards to the first guard there and kill him. Continue donig this for the rest. The last two you have to do quickly or the fourth guard will see you.
Level 7: Go hide in the grass. Go to the guard moving back and forth, and wait for him to walk away from you. Snap his neck. Move to the guy walking in a square. Wait until he's at the top-left-most part of his pattern and snap his neck from the grass. Use the grass to kill the guy at the top right. The remaining guy you have to use your C4 charge for. Use the C4 charge right near some grass, hide in the grass, and wait for him to come. Boom, you win.
Level 8: Go to the bottom of the level, hide behind a wall, tap it, break the guy's neck. Open the door and tap the wall, break his neck. Move the box out of the way and use the switch. Tap the wall and break the guard's neck. Use C4 on the boxes. Open the door, tap the wall, break his neck, you win.
Level 9: Put the box on the pad, put a C4 charge right next to it, go up to the door, blow up the box. Yay.
Level 10: Hard one. See the segment of wall that looks kind of like an "L"? Tap the wall AT THE BENT PART, then run over the the end, hide there. Run right behind the guard and around him. Now, go to the pressure pad, tap the wall while you're stand on it, run aroudn the top of the wall, and you win.
Level 11: Push the box up right behind the wall so that the guard has to walk around it (Do NOT put it in his path or he'll break it) Tap the wall, and push the box so you can get in there when he's out. You win.
Level 12: Use your map. Find which wall has a gap in it, then tap the wall and break their necks as they come by. The third guard's a bit farther away, so you have to get up on the side of the wall, tap it, watch him run at you, hide behind the wall, and break his neck.
Level 13: Open the door, hide behind those two boxes, tap them, break the guard's neck. Open the next door, tap the wall, break his neck, search the lockers, use the switch. In the room you just opened, tap one of the stacked boxes, then break the guards neck. Move the closest red barrel left one, and place a C4 charge between it and the two regular barrels. Use the switch then search the locker. Go to the next room you opened. You know the drill, tap wall, break neck. Then search the computer. Go to the exit, place a C4 charge, then open the door. You win! :D
Level 14: Put a C4 charge on the pressure pad, then run to the door. Detonate it, then wait a few seconds. Boom, you win.
Level 15: You just have to time your explosion right. >_<
Level 16: Open the only door you can, then run along the wall, and keep going right until you see anotehr door. Open it, tap the wall, break the guard's neck. Search the locker, then go back to the exit. Blow up those boxes with that C4, then break the guard's neck inside. Search the lockers. Now you can open up that door to the guard who's hiding behind some boxes. Open it, tap the wall, break his neck, search the lockers, sue the switch. Go to the room you just opened, push the chair out of the way, search the computer, then open the door to the exit.
*CONTINUING IN NEXT REVIEW, CHARACTER LIMIT :P*
Sorry, I'm stuck on Level 19. Can anyone help me? :(
By the way, awesome game. Loved it.