I played on Linux using Wine.
The main menu has mouse hover effects, but many other interactable elements do not, including the Options. In the options the Sound option does not provide any feedback on if it does anything. It would be good to add an indicator of the sound level/mute there, as well as playing a sound to indicate the volume.
The biggest thing I noticed was once I started the first level. I could click on the towers, tower type tabs, and the sound button. The sound button toggled when clicked, though there were no sounds to see if it did anything. Clicking on a tower selected it, but it appeared at the top left and clicking most places made it deselect. Pressing the keyboard keys indicated or clicking in most places, did nothing. Even trying to press escape to pull up a menu did nothing. Eventually I started pressing everything and found pressing space would advance the dialog. With the dialog blocking most actions, it should start with indicating how to advance it. I would also add the ability to click on the dialog to advance it, as well as allowing escape to work even when it is shown.
I like pixel art. Overall the art is decent, though could use a bit more polish, including animations. The font is not always the most readable, and might be an issue for some users, though I know that being low res there is a limit to what you can do. The UI could use some work. As mentioned above, mouse hover indicators being added to other interactable elements would help. The tool tips for the towers could use a bit of refining to make the info easier to read at a glance. I'm talking about organizing the data a bit so the details are better spaced/positioned. As an example of something that could be improved, the first tower has the word "range" on one line, while the value of the range is on the next. It would be better if these were on the same line. Cost has no space between the word and the value, but the others do. I'd also give a bit more space between the cost and the text "dmg", making it more like 2 columns. From the look of it I think that whole section with the stats is one big text field, so I know formatting that can be a pain sometimes. You may want to separate it out into multiple fields, or perhaps do some padding of the values before combining them to get the right positioning. It would also be good to update the text with more consistent formatting, such as capitalization. There were a number of typos/spelling/grammar mistakes in the text throughout.
I like playing tower defense games, and this one was pretty good for the early state it is in. Once I figured out the basics I was able to play through all the levels, with only a few where I took any damage on the first try. It would be nice to have a bit more detail on some mechanics, such as the speedup offered by the tower saying it improves nearby towers. What is the range? How much of a boost does it offer? Does it stack? The dungeon buildings could use with a bit more clarity of the use of those with 0 capacity and profit. It would also be nice if when you started a level you had to push a button to start the first wave so you have time to get your towers out, and to read up on any new ones. If not offering that, then hot keys for selecting towers would be nice so you don't need to move the mouse back and forth so much if placing towers near each other, especially at the right side of the screen.
Overall, this is a good start. The TD mechanics feel good and the difficulty ramps up reasonably.