Here are some questions about the demo:
Can you use the boat in the Staring Beach Area?
Not in the Demo, only in the full game.
How long is the demo?
A built-in timeout timer (probably geared toward store demo units) gives you a little over 15 minutes.
Is there any way to stop the Demo's timeout timer?
As of yet, no. If and when a Gameshark code comes out (which I seriously doubt for just a demo with the full game coming so soon), I will include it.
When I get around 90 Orbs, Daxter says something about getting a power cell. What is he talking about?
His remark has no bearing on the Demo. From what I can tell from the Behind The Scenes video.. in the full game, there is a poor elf wearing a barrel who asks for 90 Orbs to "get back on his feet". He then promises the duo a power cell in exchange for this favor.
How can I catch the Sculptor's Muse?
This is what I have found to be the easiest: Pay attention to the Muse's route. There are a couple places where he can be caught relatively easily. On the stairstep platforms at the top and bottom of the long backbone bridge, the Muse takes his time to hop on every step. By skipping steps or hopping down on him from above, you can catch him or get close enough to make a quick dash after him with the Punch button.
How many lives do I get?
In the demo, there are unlimited lives. However, there is still the timeout timer which limits the amount one can get done in one session.
How do I activate the Blue Eco platform?
First, make sure you knock the vertical bone bridge to the Mist Pillar Area into place. Notice there is a piece of Blue Eco at both ends of the bridge and one piece of Blue Eco on a platform just below the Mist Pillar Area end of the bridge; you will need all three. Then clear the Skeleton Lurker and Mud Lurker from the path (the Purple Lurker is optional). Once the path is clear, start at the Sculptor's Muse Area end of the vertical bone bridge and collect all three Blue Eco pieces then make a beeline for the Blue Eco Platform. It will activate on contact if you have Blue Eco power remaining.
How do I activate the Blue Eco Device?
First, clear the area around the Device: there are 4 Purple Lurkers, 1 Skeleton Lurker, and 2 Mud Lurkers in the area we'll be working in. Then, go to the ribcage tunnel and follow it toward the beach.. there are two steps down to the beach where there's another Purple Lurker that aren't very visible at first glance. On both steps there are pieces of Blue Eco.. so grab both, run up to grab the third piece of Blue Eco by the vertical bone bridge, jump and spin across the mud puddle, then run for the Blue Eco Device. The top of the Blue Eco Device should raise before you make contact. 15 more Orbs are now yours.
Is it possible to get all 8 Power Cells in the time limit? Is it possible to get 100% within the time limit?
Yes, it is definitely possible to get all 8 Power Cells within the time limit. Given that you need all 7 Scout Flies to get all 8 Power Cells, the completion percentage would be over 90% (how far over depends on how many Orbs Jak collected.. I've gotten 96.1% myself). As for 100%, it would be EXTREMELY difficult if it is possible, requiring the utmost efficiency in collecting Orbs and a very quick capture of the elusive Sculptor's Muse.