First one:
The noodling at the beginning goes on awkwardly long. At about 26 seconds I expected it to go into a thrashy riff based on the melody, but it kept noodling. Once it does go heavy, I feel like you switch up sections too much. The fast thrashy riff should go on for longer (I assume this is the verse part) before going into the kinda fast groove (which I guess is a bridge or prechorus). The melodic thing that plays after that sounds like a chorus; if so, it should probably repeat at some point. The thing that comes in after the chorus (at 1:57) is excellent. I would use it for a bridge. There's another melodic bit that comes in later which I didn't really see the point of and then the outro, which is very cool.
Not to write your songs for you, but if I had those riffs and was going to arrange them, I would chop the intro noodling down to about 30 seconds, play the fast thrashy riff for long enough for a decent verse, use the fast groovy part to lead into the chorus, repeat that whole thing, then use that awesome bridge part and then go into the outro. Just my thoughts listening to this; there's definitely a good song in there.
With the second I would cut down on the use of blasting; it really doesn't work too well. The keyboards are excessively fruity for my taste.
I would use the riff that comes in at 24 seconds as a verse riff with a fast thrash beat over it (rather than a blastbeat). The part that comes in at 1:10 is awesome, but I would use it as a really dramatic bridge. The part at 1:30 sounds like a chorus to me, with clean vocals. The riff at 1:55 is pretty badass for an outro of some sort. Aside from that I don't really know what to do with most of these parts.
Structurally I really don't understand what you're doing with these; they seem to be a series of disconnected parts rather than complete songs.