Tileset conversion, by 
Tileset conversions, or whatever we’re calling these things, are a tricky field to jump into, and you’re being gutsy, but this needs more work. The best recommendation I can give you is to download some successful examples of the practice — Castle 2, Psych 3, Carrotus Fix, for instance — The main thing this tileset has to offer is a different tile order, but as sonicnathan1 says, Castle’s probably not the biggest candidate for that. It makes sense to overhaul the tile order in the less used sets — Inferno, Colon, Psych, etc. — part of the reason that they’re not used so much is that people find them confusing. Castle, though, is mostly simple, and the few improvements you may end up making are offset by the learning curve someone would have to take on to figure out the rest of the set.
Beyond that, just at a first glance, your reordering isn’t actually all that good. The community is more or less agreed on the order Disguise proposes at DTR. I don’t think there’s a fixed place for animations yet, but other than that the above link is pretty solid. You’re pretty close to that, but you’ve got event tiles all over the place, which is a no-no, and there are definitely times where you fail to break tiles into sections and have the basics come before the eyecandy. Bringing the big sections of blocks that Nick added late in the game up to join the rest of the walls makes sense, but you’re not done by any means, and the tile order just doesn’t look pretty right now.
The other main point of tileset conversions is what you add to the set, why someone should download and use it over the original in the first place, and you’re really lacking here. I’m slightly hesitant about your decision to kill the slides but I imagine most people wouldn’t really care. More importantly, you add next to nothing. You expand the background stuff so it can have borders, but your colors are off, and the textured background is so traditionally colored it’s obvious you didn’t think about it for ten seconds, although you did make it work, so kudos. If you’re going to convert a tileset that JJ2 already has, you need a vision, you need to have an image of what that tileset means to you which you’re then trying to give to us to use in our levels. Right now your vision is that Castle probably has a sky outside, and that’s not good enough.
Again, look at other conversions, see that they add stuff, and maybe even go past that. Right now, this set is all well-intentioned, and you begin at all the right things, but you stop too soon for this to be useful. Study Disguise’s order, study how it’s implemented in other sets, study how tilesets can look “pretty” in JCS, and think long and hard about what tiles you want available for us before you upload. Castle is a small set, and there’s a lot of room to add stuff. I’ve never seen anyone acknowledge, for example, that the tileset as it stands is actually supposed to represent the Carrotus Castle Dungeons, not the stuff up on top. What if you looked at some JJ3 screenshots and incorporated more of that? There’s a world of possibilities out there when you’re messing with other people’s stuff.
