reeeeeeeeeeeaally nice demo!
I really enjoy your level design. Spider Hill is the one I like the less. Wind Chime 1 is my favorite. The levels are diverse and not linear.
Too bad you lost many of your levels the other day. I'd love to play the full game. x_x
I'm not sure why do you use so many "loop" objects on areas where they aren't needed. Example:

These objects do nothing. Same about Jungle Jamboree: you have lots of loop objects where passable bricks would suffice. Since the loop objects are used to disable certain bricks, they may cause bugs if the player does not touch a "loop off". Luckily, for the new movement engine we're adopting a new, more intuitive system. The "loop" objects will be kept for backwards compatibility, but they will be deprecated.
The oil ocean barrel is fine, but wouldn't be nice if the corresponding bricks get their z-index increased, so the player would appear to be "inside" them?
I'm not sure if its a problem with the engine or my computer. Sometimes the title screen music doesn't play. Neither does the invincibility music or speed shoes song.
The only problems I've seen related to audio are when too many samples are being played, they get clipped out. The audio system needs some improvements, but I prefer to leave that to 0.2.0.
Also the spikes collision box should be tweaked.
How exactly? We found a small mistake in Jungle Jamboree:

You're using a brick that looks like a spike, but the brick by itself does nothing.
And um there is no way to change the speed and invincibility music is there? ^^u
Yes, by changing their respective files in musics/ . Perhaps we'll get a new invincibility song (by Di) to 0.1.4.
Still, your demo is so much fun. Congratulations again, wrath 