These are all suggestions unless I bolded.
General:
Mp3 file is over the max size of 192 kbps. Please re encode it
Is the file not called hitcircleoverlay? You have yours as hitcircle0verlay.
You have a sliderfollowcircle.png. Please include a sliderb.png in your folder even if it's the default circle as it will clash with some certain custom skins.
Add tags to all diffs, not just hard. And remove Owl city from tags as you don't need it. It's in the artist already.
Hard has a different offset. I'm not a timing expert but I think hard is the correct (or at least better) offset. Please change easy and normal to 5,056 and remember to resnap all notes AND Kiai/SV changes.
SB:
You know, it's probably just me but I notice that when I play at the very beginning, the SB starts at the bottom and then just pops up. (Basically teleporting) Why don't you make it move up slowly instead?
Basically it starts like this http://osu.ppy.sh/ss/163799
Then at about 50ms it pops up instead of smoothly moving up. http://osu.ppy.sh/ss/163801
Easy:
00:16:438 (3) - Perhaps you could space these instead of stacking? I think it would be rather too hard for beginners to read.
00:18:964 (2) - This one I really recommend you to space. I believe beginners might not read this too well as the hitburst will obscure the approaching circle.
00:26:227 (2) - Perhaps unstack like my first explanation?
00:32:227 (3) - Unstack these as per my second explanation?
00:33:806 (3) - http://osu.ppy.sh/ss/163794 ? Avoid stacking without ruining your next pattern with 4,1 and follows with 00:36:648 (2)
00:42:333 (5,1,2) - Please space all these three per my first and second explanation.
00:47:385 (4) - Perhaps a slider here and ending at 00:49:280 would fit better with him hold "seeeeeeeee"
01:12:017 (3) - Perhaps you could space these correctly? I see you're aiming for a triangle pattern but I'm sure a little moving around and you can keep your triangle pattern while unstacking this note
01:32:859 (3,3) - Same note. Perhaps unstacking these would be nice as their approach circle would be more visible.
Medium:
Perhaps rename to normal?
I would say your settings could be too harsh for normal. Perhaps lower AR/HR/OD by 1?
00:17:701 (1,2) - These notes sound rather odd to me as they do not follow the music too well. Perhaps something like this?
It follows the music better.
00:28:754 (3) - I wouldn't really advise crunched up sliders in lower diffs because beginners won't be able to read it properly. In fact even I didn't notice because the dark BG + Dark slider didn't make me notice any slight bumps. Perhaps you could make this linear or make the crunched up slider less crunched? D:
00:32:543 (5) - Hitburst from 3 would rather make this note hard to see. Perhaps you could move 4,5 like this as it improves the flow and makes the note more visible too http://osu.ppy.sh/ss/163797
00:41:385 (2) - Same note about crunched up slider.
00:56:543 (2) - This does not follow your distant snap. Please space this correctly. I learned that distant snapping will ruin some of your original patterns/blankets but there are many more you can use.
01:00:017 (1,1) - This is totally not good. The hitburst is nearly covering the reverse arrow and thus you cannot see that 01:00:648 (1) is a repeat slider. Normally I would let this particular one go because the hitburst is nearly gone by the time you see reverse arrow, however beginners will not have the quick reaction veteran players have. Please move either the slider or note somewhere else.
01:02:543 (4) - Same note about crunched up sliders.
01:12:648 (4) - ^
01:20:859 (1,2,3,4,1,2,3,4,5,6,1,2,3,1,2,3,1,2,3) - I have to say...this whole pattern is rather cluttered. Perhaps moving some notes around will really help out with visibility.
01:24:964 (3) - Perhaps spacing this properly would be better to keep the flow more fluidly and to also avoid the nasty hitburst that will cover this circle :s
01:47:701 (3) - It's possible beginners might not see this. Perhaps you could move this somewhere else?
01:48:017 (4) - Same note about crunched up slider.
01:58:122 (4) - ^
Hard:
Holy crap SV is just so high compared to normal...I would ask you to tone it down a bit more...maybe 2.6 or so.
AR9 does not fit this song. Consider lowering it to at least AR7.
00:10:108 (7) - NC here? Combo seems rather long and NCing at downbeats are nice and it also keeps up with how you NC'd at the beginning.
00:31:278 (3) - I don't usually like that you use the same slider for symmetry but yet it's a different SV. It plays weird to me as you need to control the same slider but yet you have to keep up or slow down with them separately. I prefer you keep to one SV here for symmetrical sliders.
00:41:371 (3) - This slider is just not good compared to your first slider...please remake this one.
00:55:594 (1,2,3,4,5,6,7,8,9,10,11) - Feels overmapped. You don't need the notes on the blue tick and still plays okay for me and also fast spacing + slow slider plays weird to me. Perhaps after removing every blue ticks notes you could rearrange some better pattern and without needing to slow down the slider. You could do something like this? http://osu.ppy.sh/ss/163806 http://osu.ppy.sh/ss/163808
01:00:646 (3,4,5,6,7,8,9) - Same feels overmapped.
01:05:687 (1,2,3,4,5,6,7,8,9,1,2,3,4,5,6,7,8,9,10,11,12) - ^
01:13:898 (7) - Jump is not necessary here and feels like it's added for artificial difficulty
01:15:161 (9) - End kiai here.
01:56:213 (1,2,3,4,5,6,7,8,9,1,2,3,4,5,6,7,8,9,10,11,12) - Overmapped and Copy paste.
General:
Mp3 file is over the max size of 192 kbps. Please re encode it
Is the file not called hitcircleoverlay? You have yours as hitcircle0verlay.
You have a sliderfollowcircle.png. Please include a sliderb.png in your folder even if it's the default circle as it will clash with some certain custom skins.
Add tags to all diffs, not just hard. And remove Owl city from tags as you don't need it. It's in the artist already.
Hard has a different offset. I'm not a timing expert but I think hard is the correct (or at least better) offset. Please change easy and normal to 5,056 and remember to resnap all notes AND Kiai/SV changes.
SB:
You know, it's probably just me but I notice that when I play at the very beginning, the SB starts at the bottom and then just pops up. (Basically teleporting) Why don't you make it move up slowly instead?
Basically it starts like this http://osu.ppy.sh/ss/163799
Then at about 50ms it pops up instead of smoothly moving up. http://osu.ppy.sh/ss/163801
Easy:
00:16:438 (3) - Perhaps you could space these instead of stacking? I think it would be rather too hard for beginners to read.
00:18:964 (2) - This one I really recommend you to space. I believe beginners might not read this too well as the hitburst will obscure the approaching circle.
00:26:227 (2) - Perhaps unstack like my first explanation?
00:32:227 (3) - Unstack these as per my second explanation?
00:33:806 (3) - http://osu.ppy.sh/ss/163794 ? Avoid stacking without ruining your next pattern with 4,1 and follows with 00:36:648 (2)
00:42:333 (5,1,2) - Please space all these three per my first and second explanation.
00:47:385 (4) - Perhaps a slider here and ending at 00:49:280 would fit better with him hold "seeeeeeeee"
01:12:017 (3) - Perhaps you could space these correctly? I see you're aiming for a triangle pattern but I'm sure a little moving around and you can keep your triangle pattern while unstacking this note
01:32:859 (3,3) - Same note. Perhaps unstacking these would be nice as their approach circle would be more visible.
Medium:
Perhaps rename to normal?
I would say your settings could be too harsh for normal. Perhaps lower AR/HR/OD by 1?
00:17:701 (1,2) - These notes sound rather odd to me as they do not follow the music too well. Perhaps something like this?
00:28:754 (3) - I wouldn't really advise crunched up sliders in lower diffs because beginners won't be able to read it properly. In fact even I didn't notice because the dark BG + Dark slider didn't make me notice any slight bumps. Perhaps you could make this linear or make the crunched up slider less crunched? D:
00:32:543 (5) - Hitburst from 3 would rather make this note hard to see. Perhaps you could move 4,5 like this as it improves the flow and makes the note more visible too http://osu.ppy.sh/ss/163797
00:41:385 (2) - Same note about crunched up slider.
00:56:543 (2) - This does not follow your distant snap. Please space this correctly. I learned that distant snapping will ruin some of your original patterns/blankets but there are many more you can use.
01:00:017 (1,1) - This is totally not good. The hitburst is nearly covering the reverse arrow and thus you cannot see that 01:00:648 (1) is a repeat slider. Normally I would let this particular one go because the hitburst is nearly gone by the time you see reverse arrow, however beginners will not have the quick reaction veteran players have. Please move either the slider or note somewhere else.
01:02:543 (4) - Same note about crunched up sliders.
01:12:648 (4) - ^
01:20:859 (1,2,3,4,1,2,3,4,5,6,1,2,3,1,2,3,1,2,3) - I have to say...this whole pattern is rather cluttered. Perhaps moving some notes around will really help out with visibility.
01:24:964 (3) - Perhaps spacing this properly would be better to keep the flow more fluidly and to also avoid the nasty hitburst that will cover this circle :s
01:47:701 (3) - It's possible beginners might not see this. Perhaps you could move this somewhere else?
01:48:017 (4) - Same note about crunched up slider.
01:58:122 (4) - ^
Hard:
Holy crap SV is just so high compared to normal...I would ask you to tone it down a bit more...maybe 2.6 or so.
AR9 does not fit this song. Consider lowering it to at least AR7.
00:10:108 (7) - NC here? Combo seems rather long and NCing at downbeats are nice and it also keeps up with how you NC'd at the beginning.
00:31:278 (3) - I don't usually like that you use the same slider for symmetry but yet it's a different SV. It plays weird to me as you need to control the same slider but yet you have to keep up or slow down with them separately. I prefer you keep to one SV here for symmetrical sliders.
00:41:371 (3) - This slider is just not good compared to your first slider...please remake this one.
00:55:594 (1,2,3,4,5,6,7,8,9,10,11) - Feels overmapped. You don't need the notes on the blue tick and still plays okay for me and also fast spacing + slow slider plays weird to me. Perhaps after removing every blue ticks notes you could rearrange some better pattern and without needing to slow down the slider. You could do something like this? http://osu.ppy.sh/ss/163806 http://osu.ppy.sh/ss/163808
01:00:646 (3,4,5,6,7,8,9) - Same feels overmapped.
01:05:687 (1,2,3,4,5,6,7,8,9,1,2,3,4,5,6,7,8,9,10,11,12) - ^
01:13:898 (7) - Jump is not necessary here and feels like it's added for artificial difficulty
01:15:161 (9) - End kiai here.
01:56:213 (1,2,3,4,5,6,7,8,9,1,2,3,4,5,6,7,8,9,10,11,12) - Overmapped and Copy paste.