Hello salem44, welcome to the forum.

First: get rid of friggin walkthroughs; the game is most fun exploring on your own!

Besides that they take away the adventure, they can also make things unnecessarily complicated, while the game gives it all!

Get the basics in your fingers and mind.
It's very simple but you must learn to run, jump and grab. Run = Left-shift key (left hand little finger), Jump = Spacebar (left thumb), while middle finger is on W ("forward").
The Spacebar to jump: a swift hit on it to make a little jump, or hit and hold to make a longer jump.
I think i couldn't be more precise trying to describe the ghoul chase part:
The ghoul steals the crystal.
You Jump through the window (space + W),
btw, on the floor you can pick up the hammer (if you haven't picked one up before, to make sure you have one which you need later in the game)
go left towards the second ladder and climb
Now don't get too hasty or you'll fall, but just don't stop, the ghoul isn't waiting forever.
Follow the path through the burnt rooftop, gently jump down, follow over the roof top and jump down.
> New map load <
Sareth says "It's gone!"
Look (only move mouse) to the left, to the opening and the rooftiles.
Run through the opening, turn right over the roof, turn left, and jump (Space + W) into the window
Turn to the right.
Sareth says "There it is"
Now hold L-Shift + W to run, turn left following the ghoul and through the opening, jump (hit Space, while still keeping holding Left Shift + W) across to the other roof, turn to right and then left into the first window.
Ghoul escapes on the left, throwing furniture; run around it or jump/run over it (Left Shift + W + Space) and kick the planks that barricade the dooropening
walk/run over the wooden planks across the other roof, turn right
jump/climb (W+ Space-hold) to lift yourself up to the higher roof,
run and jump-climb (W+ Space-hold) to the third higher roof
turn to the right and walk to the end of the rooftiles,
over the double planks, straight forward passing the grass and trees,
as soon as you approach the ledge and Xana says "You can't hesitate now", make sure you're holding L-Shift + W then add only a very swift hit on the Spacebar to make the jump into the room,
follow the planks upwards, jump up twice (while still holding W, hit Spacebar twice)
through the window
carefully (just hit W swiftly) go down onto the rooftiles below
turn (just move camera = mouse) slightly to the right (at 2 o'clock)
Now hold L-Shift + W to run, then add and
keep holding Spacebar to jump across to the opposite roof with the two windows and grab up (holding the Spacebar is essential for grabbing, if you don't hold it you'll fall down).
Into the second window
so you can take ("E") a few hams
turn to the left where the ghoul went, through the rubble
Xana says "there's no other way, jump!"
Hold L-Shift + W to run, + swiftly hit Spacebar (do not hold!) to grab the chain and climb up, slightly turn towards a safe wooden floor and (hit Space very swiftly again to let go) to land on it
Another burnt down rooftop at your left, pass through it and turn left again
Run (hold L-Shift + W) then jump (add Spacebar briefly) across the abyss towards the broken wall of the castle and turn left
while keeping holding L-Shift + W run towards the edge then briefly add a hit on Spacebar to grab the chain, hold W to climb up a little and jump onto the next roof
run it to the end, walk/run onto the wooden floor (at this part be careful and don't jump or you'll break the old rotten wood and fall down)
follow the wooden plank up, to the right, down, and up then hit + hold Spacebar to grab and climb up onto the castlewall bricks, turn left, left again, follow the top of the wall towards the dooropening at your rightside and enter the castle.
I hope this helps.
