Huh, you know this is actually an interesting little concept. I like the whole "catch the key or it'll unlock what's below you" thing, which leads to the end after a bit. It makes me curious if it has any meaning behind it, or if it was just a neat idea that came to mind.
The gameplay itself I didn't find incredibly enjoyable, to be honest after catching the keys for a little while I grew a bit tired of it and let most of them drop so I could see what would happen if you fall. I was pretty surprised at how long it took for the game to end, which isn't really a great thing.

In the end it could be more polished with more fluid controls (player velocity and friction, not that hard to implement really) and with perhaps even a bit of narrative woven in with the gameplay. But it's a good job for a first project with as3.

This is a good overall tutorial on handling smoother movement:

http://asgamer.com/2009/as3-flash-gam es-for-beginners-more-advanced-charac ter-movement

I would also suggest taking a look at that from the beginning of the tutorial if you'd like, it may seem confusing if you program on the timeline, but it's really not that much different with setting up a document class like they did. It can seem pretty difficult in the beginning if you aren't accustomed to that though.

I thought that was fantastic. I played through it but don't want to spoil anything for anyone else who may read this. This really has great atmosphere, and really reels you in with the narrative. Great job, I really had a great time with this.

I found the art very refreshing and nice. The game play itself wasn't anything really special to me, but overall it's not a bad game. I enjoyed the bit of time I spent with it.