The CE is worth the price just for one of the HOS in the additional play--everything moves-really cool! Graphics in the rest of the game are very good.
Some of the HOS are interactive. If you pick up an interactive item and can't find out how to use it, a right-click releases the object. Some objects are easy to find, others are more subtle.
Story line is a bit fuzzy imo, but then time travel is pretty fuzzy, isn't it?
The time machine can tell you where to go next if you get stuck, hints are helpful, but not too much so, although hints are vague for some of the mini-games. Strategy guide isn't needed often, but does help for the mini-games with vague help hints.
Music was OK for me, although it got awfully boring while working on the harder mini-games.