Single player, by 
I am going to hurry up and give you a helpful review before everybody jumps on the bandwagon and criticizes you for this. Which I’m afraid, they will.
First off, I’m giving you one point because this is your first level (As you said), and I usually give first levels a +1 point. But there are some serious flaws. Your level construction is almost okay, but I could find nothing preventing me from simply finding a high spot and helicoptring to the end. That’s poor design there. There’s no eyecandy. No music. Not even a name! There were some events, but these were very poorly placed. The tileset was also very underrused. The level, overall, looked massively unfinished.
I can help with some of this. First of all, fill in all the gaps. Unlike in some games, the edge of the JJ2 maps is not a death pit, you will simply float there and frustrate yourself in playing. Fill in the holes.
Next, deal with eventage. Most if not all the enemies are in small holes guarding events. What ones aren’t (and these are predominately aerial baddies) are strewn either randomnly or in clumps. Take a cue from EvilMike’s singleplayer beauties. Or some of Agama’s wondrous levels. There’s lots of good examples out there, and you will learn a lot from ‘em. Food and misc. is also clumped, somewhat few and a wee bit far between. Some ubercheap powerups [a.k.a. PU’s] like the seekers are placed right in plain sight, not providing much of a challenge to obtain. There’s plenty you can do to fix it.
Add a good song. Music is literally a little less than half the importance of any good pack. If you use a circus song on a spooky level, that won’t work. If you use a sad song on say, Discoland, that doesn’t do it either. And let’s not even go into disco music’s do’s and don’ts. I would recommend some kinda fast medieval songs for your level, or even just the plain Medivo song (Which if you have JJ2, just go to level properties and type “Medivo”. A tip: Any non-j2b format song will require you to add a file extension on the end. Some good ext’s include MOD, XM, S3M, IT, or even MP3 and WAV, what with the new JJ2+ progs)
A level name is good too, but I won’t launch into a long spiel about what to name it. You should be able to come up with something.
Next, and perhaps most importantly, add some good eyecandy eyecandy period, to your level! Ask anyone on J2O. You won’t find a single person who won’t say you need good eyecandy to make a good level. Do you know that there are 3 foreground layers and 4 background layers in the JCS? There are, so use them! Put a gargoyle in here and there. A column of rock in the foreground (though be careful how you place baddies around these). A flag rippling in the breeze. The unmasked rock bg. There’s any number of good and perfectly fine things to be done with eyecandy, so make sure you do at least some of them. And layer 8? If you look in the editor, you should see that there’s a background image for the level that’s 8×8 tiles. If you click “textured bg” in the layer 8 properties, you can make your bg twice as good. And certainly better than the one you have now.
I don’t think I need mention buggage. Always, always, ALWAYS go over and check your levelsfor bugs. I can’t stress that enough, as so many people (myself included) have fallen hard for not making sure they had a clean level. Make sure the masks are all good. That you can’t get stuck in any spots. That events and enemies aren’t placed so’s that they’ll kill you as soon as you get there. Check, check, and check again. Okay, I DID kinda mention it, but it is that important.
Finally, gameplay. Your level, I’m sad to say, didn’t have a whole lotta it. It was mostly back-and-forth-go-down-and-end. Add some warps to spice it up. Use trigger scenery (That’s a whole nother discussion—read the wiki entry here or ask one of the older sages of J2O to learn more.). Add some variety in the level, but don’t make it too long or too short. Eventually, you’ll find the right balance. Get some friends to test stuff out for you, to make sure you won’t make a colossal flop out of your dream project.
So, what can I say? This turned out quite a bit longer than I had intended, but I think that’s good. You’ll hopefully learn something from this, or I haven’t done my job. I’m so glad you put your stuff up here, but make sure it’s only your best efforts you add. Many many site members take a dim view to half-baked stuff, so do your best and don’t just churn levels out like a conveyor belt. You’ll get it eventually. I know you will.
2.0, but no dl rec. You just need a little more time. Hang in there, you’ll get your chance soon enough!
Keep Jazzing!
PT32
EDIT: I have this nagging feeling that I wrote this review kinda treating you like a newbie. My profuse apologies if you saw it that way too. :(
Note to Minmay: I heartily agree.
