I'm not sure if this question is appropriate for this site, but I'll give you my take.
First, kudos on making your game! I am all for doing stuff yourself if you can't find anybody else to do it.
You are certainly going for the pixel art retro look, and that is pretty cool. Make your game in the way you like it the most, and take people's advice just as advice. Stuff people tell you (even me) are not orders, and feel free to disregard everything you hear, or even do things completely differently.
That said, I have some suggestions to make your game look a bit better. I'll be based mostly on your last screenshot.
Decide what your resolution is, and stay with it. It seems like you are mixing lots of pixel sizes, and it makes things look pretty inconsistent. For example:
The rightmost block in the "P" in "HP" is on a 1-pixel grid.
The other GUI fonts are on a 2-pixel grid. The mouse cursor is also on a 2-pixel grid.
The background floor, and the world in general is on a 4-pixel grid.
The items and other GUI elements seem to be on a 6-pixel grid, but the exclamation mark seems to be on a 4-pixel grid. Some pixels on the top right elements are on a 5-pixel grid?
The close up character is on a 16-pixel grid.
So, in general, the pixel feeling is completely lost. Choose a resolution, and make it so every graphical element uses that resolution. If you're going for an 8-bit taste, you may want to consider using a relevant resolution, like 320x200 (CGA), and then upscale so it can be seen on a modern monitor.
Once you choose a resolution, make all of your graphics target that resolution. I know you are using the small character sprite and upscaling it, but if you were back in the 80s, a close up would be an awesome way to show more detail in your character!
Same goes for your color palette. The entire point behind retro is that you are extremely limited on resources. That goes for colors as well. If seems like you're using arbitrary 24-bit RGB colors, but an 8-bit platform does not have all these colors! Restrict yourself to a very small palette, like CGA's 16 base colors, and make your game with only those colors!
You'll notice those colors are hideous! but that's the beauty of 8-bit. Using very tight restrictions to make awesome stuff.
For resolution and colors, it could be a good idea to choose a target platform, and try to emulate its restrictions, at least in terms of resolution and palette.
Choose a font, and a font size, and stay with it. This is true for most games though. So far you're using four fonts (excluding the game title's font): the Start/Exit font, the top HP/MP font, the "Knight" font, and the other font. Choose (or even make!) a font, and stay with it for the entire game.
Ditch any kind of effects. You seem to be using a semitransparent curtain to black out the world and show the character details, but such effects would be completely unavailable on an 8-bit platform.
If you're going to show a character details screen, make a character details screen as a separate screen, or at least make a general border for all your elements.
I would say ditch the mouse. Mouse in games is much more modern that what you're trying to emulate.
Maintain consistency in your terminology and the way you show things to make things more understandable. If "HP" and "Health" are the same thing, why do you call them in a different way? Why do you show one with a bar and the other one with numbers?
In general, when showing lists of data, you may want to align the labels and data so the flow is more understandable. For example:
PlatyPi the Knight
HP 125 / 125
MP 10 / 125
If the player is on a menu, let them know of the fact they're on a menu, such as with a title "Character details", and let them know how to get out of it, such as "Press ESC to return to game". Make sure all keystrokes and icons are consistent (ESC always goes back one menu, titles always go on the top, text hints on the bottom, etc.)
"Adventure Quest"? ;)
This is just a bunch of very basic ideas that I think could help you make a better looking game. If possible, partner with somebody who has a bit more of an artistic background, and discuss your ideas with them.
Also, look at other games of the same era that you're trying to emulate, and learn about the platform they're on. Try to emulate what they're doing, and you'll have an awesome game!
Once again, congratulations on making your game, and good luck!