Battle, by 
Ah, this takes me back. These levels are what you’d see in 1998 or 1999 or so, a time when the distinction between battle and hotel levels could still be pretty loose and JCS was notable not because it let you make battle zones perfectly in tune with specific theories of gameplay but because it let you build your own worlds and populate them with distinct features and environments. That is, incidentally, the only respect in which the music chosen really makes any sense. It kind of works in the Top Secret level, but for the other two levels the music is totally wrong, and can only be saved if you consider that it came from a Castlevania game, and these levels are much closer to that in design then they are to ordinary battle levels.
Probably the best-known comparison for these maps is Hotel Orion (and to a lesser extent many of its cousins): the eyecandy is minimal and individual tiles are blocky, chosen to convey specific ideas about what’s going on around them rather than to create a beautiful, unified image for the entire level. This is eyecandy as one might find it in Cracco Land of Coins, but even more broken down than in that. In the Top Secret map in particular — my favorite, and the best example here of what I’m talking about — the author uses letter blocks to tell you what the place you’re in is. “3 Way Arena” is all you need to understand that you’re in an arena where you fight with powered-up RF Missiles, because that’s the only thing around. The maps are segregated — sometimes by elaborate warp systems, sometimes by empty space — into very specific areas for very specific ideas. You’ll never find speed dating (or even a chatroom) in a level of today.
It isn’t that the author doesn’t know how to use JCS, and so doesn’t produce what we’re used to. There are plenty of destructable scenery, springs, floats, trigger crates, and warps, all working flawlessly. The other layers are populated and have had their settings changed — they’re not remotely attractive, particularly in Bloxonius, but they’re technically proficient. One particularly intelligent area features animated tiles that remain solid for a while, then change to smiley-face blocks to indicate that they’re about to disappear, then go unsolid for a bit so you can fall through. Next to them are countdown animated tiles so you’ll know how much longer you have left before escape is possible. This is the kind of thinking you’ll see in these maps but would never see anywhere else, at least not so primitively.
Right now, these maps are mostly unplayable for anyone but the author and whoever lives in real life proximity. None of us have the right endearment or can actually understand the importance of the place in the Space Warbase level where you fall through collapse scenery and collect ammo, and the moving columns make no sense to us. But this author has everything it takes to improve later on. The author needs to decide what is most important in level design, fast-paced gameplay or worldbuilding — clearly right now the latter, but things may change — and separate the two out. The vast quantities of ammo right now are torn between being actually used for battle games and for invoking specific sentiments, and that’s not right. But it is from levels like this that a new Craccoboy or Miracle of Sun might eventually evolve, although a little more time spent on eyecandy might help, at least to sell concepts to casual players. And making the levels smaller would be a good step too, so that the author can actually focus on places for more than a minute or two before having to move on to fill the rest of the enormous layer 4.
If you’re looking for battle levels, absolutely do not download these. But they’re wonderful reminders that there’s a lot we could be doing with JCS that we’re not right now. This author doesn’t yet have the skill to make it palatable to a wider audience, but maybe some of us do. Or maybe it’ll take another couple years. If you do download these, maybe skip the Bloxonius map (battle4s) entirely, as it’s more of a battle level than the other two but a throwback to a school of design we absolutely do not need. But try to keep an open mind, and ask yourself if what you see is necessarily worse than what we do in JCS today, or just (a very primitive, experimental version of) something different.