Alright, Mirror. I apologize if my initial reaction was a bit harsh. I tend to get angry at levels with huge problems like yours had.
I see you fixed the glitchy areas, and they look a lot nicer now. I also found those secrets you eluded to.
However, the level still has a lot of construction issues. If you deal with the following appropriately, I will change my review of your level to a more positive one:
-Build/rebuild more areas to eliminate any and all possibilities of reaching void screens or ending up in a wallswim.
==One of my biggest gripes is an area in screen x999 y1000 where you fall through the floor into a wallswim.==
==Additionally, you need to fix the room directly below the last one mentioned so not only can you not climb through the ceiling into the floor of the room above, but you also do not run right into the water on the right side. Put a ramp there or something.==
==In room x1002 y1001 (where we get the high jump), there still exists a hole in the wall which leads to a wallswim. You should patch that up or turn it into a proper secret.==
==In the pink mountain area, you need to apply more sky screens so that players do not jump off the tops of mountains into void screens. The same needs to be done as well for the entrance to the umbrella cave, the area where you start, and the snowy mountain region.==
-Apply blue Detect Target boxes around your secret areas so people with detectors will know that they are secrets.
==This is simply common courtesy. You can find these tiles in the System category under 27 (for a faint green glow) and 28. (for a strong green glow)==
-Use more ambient sounds in places where appropriate. (I.e. anywhere outdoors or in caves)
==Here are some suggestions. For any scene involving a waterfall, use either atmos 15 or 16. For any scene involving pools of water, use atmos 13 or 14. For any scene involving a cave that isn't full of water, use atmos 3, 4, 7, or 9. For any scene involving a clear sunny day, use atmos 6, 10, 11 or 12. For any scene involving electronics, use atmos 20 or 21. And so on.==
-Be wary of how certain moving creatures and knytts act.
==On x1002 y998, one of the knytts can be seen walking on thin air. You typically don't want this to happen. On x1006y997 upon entering the screen, the rabbits glitch over to the right side of the screen, due to them being trapped in solid tiles. If you wanted rabbits to run under the mountains, make the bottom tiles in layer 2 or less so they can.==
-Careful how you set up some of those challenges
==In x1000 y 1001, the cave babies on the ceiling are simply placed in a line along the hall. This might surprise someone the first time, but after that, you can just run past them forward and backward without any resistance whatsoever. It's kind of pointless. In x1030 y1003, you set up a bunch of spike blocks and cave shooters to present something more complicated to get past, but it is just a mess. The spike blocks go all over the place, and we really do not need to be reminded to use the hologram powerup here. Here's a tip to improve this section, replace the one-block spike blocks with the 4-wide spike bars (Traps, 1). Those are much easier to manage and do not go all over the place. They also allow for more precise challenges.==
Take care of all of those, and you will have a solid first level. Good luck to you!