So, yesterday I finished my first map. My first concern is the quality of the audio sample on the webpage https://osu.ppy.sh/beatmapsets/1068047#osu/2236055
The audio is perfectly normal inside the game, but the sample on the internet sounds like it's been made 20 years ago.

Next question. When using sliders (and spinners), they have a hitsound at the end of them by default. But I've noticed in many maps that the end of a slider is silent. Because of this, I avoided using sliders too much, because the second hitsound doesn't sync with the song most of the time. Do people just replace the second hitsound with a silent one? And how do I do that?

Now about my map. I already know that the difficulty of the first and second halfs are inconsistent. However, a higher difficulty suits the second half. So do you think I should remake the first half to make it a little closer to the difficulty of the second half, or is it fine even like this?
At last, if any of you are kind enough to use a little of your time to try it out and give some feedback, I'd appreciate it.

In most of cases you should question the slider itself if its end doesn't sync with the song.
Often people just turn down the hitsound volume to 5% and use the soft hitsoundset for the sliderend as it has the lowest basevolume of the standard hitsounds. Using a silent hitsound is also an option though.

If you want to learn more about hitsounding I recommend checking out this map in Edit-Mode:
https://osu.ppy.sh/beatmapsets/224758#osu/524469 (read the map description first)

Regarding the preview:
I believe that is just the preview audio being degraded in order to save filesize on the server. You have to imagine that basically millions of audio previews are hosted on the site. Don't bother with it.

Endaris wrote:

I believe that is just the preview audio being degraded in order to save filesize on the server. You have to imagine that basically millions of audio previews are hosted on the site. Don't bother with it.

That makes sense I guess.

About the sliders - I'll probably try to only use them where they sync, even if it makes my map consist 90% of circles.

Don't worry about audio quality on webpage, it's like that for everything. The in-game audio will be fine.

About sliders, the end doesn't necessarily have to sync up with a note. It can instead sync with the end of a held note, which is something circles can't do well. Here's some examples in a ranked map

Razihel & Virtual Riot - One For All, All For One [deetz' Expert]
https://osu.ppy.sh/beatmapsets/275655#osu/695636
The following timestamps show some examples
00:32:307 (1,2,3,4) - These 4 sliders each represent the beginning and end of a note
00:39:756 - 01:06:238 - Every single slider in here starts and ends it's own note, most of which are longer than one beat
02:05:411 (3,4) - These 2 sliders each represent one note
02:45:549 (1,2,3,4,1,2,3,4) - These ones do that too
And many more you can find

Notice how even though the hitsounds are audible for most of these, they don't sound out of place. They are filler notes, which don't exist in the actual song but don't break the pace. Also notice that these filler notes are only ever slider ends and never a slider head or circle. This is because slider tails are passive and don't require a click so players never have to click tune. pishifat (a relatively well known mapper and youtuber https://www.youtube.com/user/Pishifat) has a video about filler rhythm (https://www.youtube.com/watch?v=87CX7bxov7o) and mapping advice in general so I advise you check him out.

Keep in mind that I am not a veteran mapper - I am pretty new to mapping as well - so take my words with a grain of salt. Also because of my lack of experience, I can't give a good answer to your question about the difficulty spike. However, I personally feel that the second half isn't hard to play, but it was very hard to see where everything was. Yeah I'm not a very good player, that plays a part in it, but I can usually confidently do 4* maps, so I think it really is a bit too hard to read.

Once again, please keep in mind that I'm a new mapper too (only one map total and it's WIP) so don't follow my words blindly.

Don't worry, anyone can leave feedback, it helps me, because you're the only one anyway ^^
I had a hard time clearing my song myself, but I normally play maps under 4*, so that's probably not surprising, but that's mainly because of the speed and pace of things, not due to being too diffcult to read.
But my experience is probably a little biased, because I know the song very well and so I'd know how things are going to go...
In any case, thank you.

Do you want to do a M4M (mod for mod) with me since we are both newbies? I'll mod your map and you mod mine. How about it? We'll learn how to mod as well, which is very helpful when requesting mods since most people prefer M4M.

nice