Nice!
There is a little performance issues here and there, a little shaky and that can be because they are young. It doesn't seem that they believe in their own performance. Teach them to play with confidence!
For the technical thingys, I feel that the guitars on the first song (demo1) is a little too reverberant. Maybe HPF that reverb return? The vocals is a little too dominant over the music. Makes it a "vocalist showcase" instead of a band effort.
Demo2 has a different snare going on, sample replacement? It works though, better than the first. Makes it the drums feel a little more important. The vocals is a little pitchy, and it seems a little too dynamic. Compress or automate the vocals a little bit more. The guitars works here, really ambient. A like them, reminds of A perfect Circle.
Demo3 has the best vocal of them all. A little muddy in the lower mids, cut a little at 400 hz, and boost a little air at 10-12 kHz and they will be fine. Guitars seems a little to fizzy, it might be intentional but I feel like lowering the 1-2 kHz a little and high-pass them. Again the performance is a little shaky, but that is only practise practise practise. Like the end guitar lick is like 5% over the guitarists ability right now.
Great job though! The overall balance is really good, the tracking seems spot on, and I am nitpicking. It's great as far as demoes go! The mastering part is really good, you got the levels up, now pumping or other artifacts that I can hear on my lap. Good job!
I didn't now there were more recording/mixing geeks here?
