Sounds like music I wrote when I first started writing.
You have a good sense of form. => You don't play the same thing for too long, and change things up appropriately.
You have a good sense of tonality. => There were a few strange choices for chords/notes, but they weren't horrifying or completely indefensible.
You can tell these were written ON a guitar, because of note spacing. Just something I notice as a guitarist. It's nice.
Suggestions:
If you aren't comfortable with adding other instruments, like drums or bass or vocals, start by adding another guitar. The first two tracks you have are actually quite perfect, if they were accompanied by another guitar playing a melody line. If you want to get really complicated, you could try working in a melody to the already existing guitar part ... but that might be tough, lol. (Think classical guitar.)
Criticisms:
All of your songs are in 4/4. Not only that, but every one of them is 1 2 3 4 |1 2 3 4 |1 2 3 4 |1 2 3 4 |1 2 3 4 |1 2 3 4
This can make your music monotonous. BUT. As for #1 and #2, you COULD keep them monotonous, and add that second guitar for a melody like I talked about above, and have THAT guitar use some more rhythm.
Ex: First guitar is like 1 2 3 4 |1 2 3 4 |1 2 3 4 |1 2 3 4 | 1 ...
Second guitar is like 1 ... 4 | .... 3 .. | ... 2 ... | 1 .. 3 .. | 1...
Try adding some sustained chords, since that first guitar is just playing short notes.
Or try letting the notes ring on the first guitar.
Check out the thing I attached. Hope I'm not stepping on your toes or anything by going ahead and playing around with your tune. You can use whatever I came up with, I don't mind.
The third one: There's something to it, but it's very rough compared to the others. But the rhythm is more interesting, and it even changes tempo! But this kind of music NEEDS drums/bass/etc.
As for the last one: You're going for something more cinematic, or atmospheric. The plodding 1 2 3 4 |1 2 3 4 does not lend itself well to this genre. Make it more free. Ignore bar lines. Let chords build up and swell and gradually fade away. Losen it up.