Unfortunally the chest haven't a great treasure insight ...

... And that was for me a little bit disappointed ... all the effort to reach the chest twice!

.... first without key, than with key ... many times falling down ...
On the Xbox I discover it is handy if you use the trigger when jumping (the trigger to focus on thing/enemies!) !
When I use the focus (to have a look over my shoulder) it goes really better for me to jump and reach te next "platform"!
I used it also by all other puzzle where I must jumping from platform to platform!
And further on Raze have given good tips for jumping!
thanks, you're great.