Best and/or hardest online puzzle games?

I'm looking for some online puzzle games that are really hard to figure out or beat. Something like the "Continuity Game" (Google it if you aren't sure what it is). I want something challenging, not time-wasting.Best and/or hardest online puzzle games?
Try http://www.cartosmagicmaps.com : )



I just love the art in there!Best and/or hardest online puzzle games?
Look for:



Portal (Proper game of +-800 mb)

Machinarium (Flash game of +- 300 mb)

Closure (Flash game on website)

Epsilon (Flash game on website - www.armorgames.com/play/1642/epsilon)



Let me know if you need help finding themBest and/or hardest online puzzle games?
Puzzle Games