Boss Battle is currently my top level. It has over 2000 Downloads and over 100 Likes! The beginning has 2 short, but challenging-ish, levels, and a boss fight afterwards. Note that this level is incomplete!
Level 1 Edit
Coin?: Yes (1)
Main Part Edit
To complete Level 1, jump up onto the first descending platform. Shortly after, jump up onto the next platform that drops, but don't jump too high! As soon as you land, jump once again to land on top of the first cloud. Now jump as high as you can, and tap on the green swirly thing. This is an invisible green jumping ring with some decoration on it to make it "visible." You should land on the underside of the second cloud. Almost at the very end, jump as high as you can go, skipping the visible green ring. You will land in a big blue swirly; this will change your gravity to normal. Land on the tiny cloud and quickly do a moderate jump. Use the invisible yellow ring (once again with swirlies to make it "visible"), then the green one, and finally the pink. You will now end up in Level 2.
The Coin Edit
To obtain this coin can be tricky. On the first platform that drops down, quickly tap/click (but not too quickly!) so you go beneath the second descending platform. A very short time afterwards, you will go over and invisible gravity ring; use it. You should now be on the underside of the first cloud. Now just continue the level as normal... almost. Right before entering Level 2, you should grab the coin in between, but also above, the green and pink jump rings.
Level 2 Edit
Main Part Edit
Level 2 is much more deceptive than Level 1. Do not follow the green arrow. Instead, go right where the bottom blue and orange thing is. Those "things" will kill you if you touch it, but this one will move down so you can pass through the gap it creates. The next set of "things" is very similar. Once, again, don't follow the green arrow. Aim yourself in between the two middle "things." The top ones will move upward enough for you to fly through.
In the next portion, you must grab the blue key. To do so, avoid the "things" (I really need to come up with a better name for them) to grab it. Immediately tap/click! You will activate an invisible pink ring, but it will send you up just enough to avoid the other "things." Now fly through the gap in the pillars.
There is a brief intermission between Level 2 and the battle. Enter the Cube portal low! As soon as you do, tap/click to use the yellow ring. Tap/click repeatedly once you enter the Wave portal to avoid hitting the spikes. Be warned! After a short amount of time, the whole thing will move up, then back down. Be prepared.
The Battle Edit
Coin?: Yes (2)
Main Part Edit
Grab the green keys, avoid the red keys. Grabbing the green keys will damage the boss and allow you to progress in the fight. Grabbing a red key will result in immediate/shortly coming failure. Avoid all obstacles. In the section with the 3 consecutive platforms, jump on them. If you don't, the boss' attack will immediately kill you. Don't land on the third platform. Instead, grab the key. If you don't, the boss' attack will kill you. Avoid the spikes in the next section. They move slightly up and down, so be careful and do small jumps.
Resting Time! Edit
There is now a very, very short resting time.
Jump a fair distance before the red "!", as it will move upward along with spikes. On the third "!", don't jump. You will go underneath the spike and grab a green key. Now avoid the red spikes, but on the third set, do a very small jump, as the spikes will move down.
That is as far as I've gotten with this level.