Hey, thought I'd stop by and give these a shot.
EDIT: I somehow missed reading that rockets were a main part of the theme in this chapter... I feel really stupid for being surprised by them in each level now. Sorry about that!
1) Looks nicely decorated, I like the touch of the "bulb" made of a sun in the lights. The telescope is pretty cool too and the little touches outside the play area like the salt streams.
Also really like the idea of the blade that speeds up as it "rolls" downhill. I almost thought I was looking at a gray lava ball for a second. Only criticism for that is I would have it start outside the little house you get the key in, just so you have a spot to catch your breath for a second (personally I think very important when you have rockets always on your back). At the very end, I find it rather frustrating that there is an opposition between the conveyor belt and the fan, then you add in the saws around you and the missiles outside and I didn't really enjoy that part very much. Tried it about 30 times but never made it around the last blade. Maybe just a regular floor here would be a little better... but that's just me.
2) First impression: lovely color scheme, lavender, copper, and yellow are an interesting combination. Died a bunch of times just trying to get out the bottom of the saw tunnel. I personally find lots of missile launchers in a level to be rather annoying... I appreciate that you at least locked them away for a moment. Died about 15 more times before getting to the final tunnel. I think I'm home free and them BAM right into the wall saws... cruel! I was able to beat this one. Just took a bunch of tries. Not too bad.
3) After hearing my opinion on missiles in a level, you could guess how I'm going to feel about this... I totally get what you were going for, but I didn't really find this to be very fun. Dodging missiles and doing tiny hops, then waiting in front of a wall just kind of goes wrong with me. I'm sure there is a way it could be spiced up a bit so it feels a little more dynamic though. Maybe breakable tiles in a wall you can run behind, then snipe one tile out of it for the rocket to shoot through (a set for each group of walls)? Idk, just the first thing that popped into my head.
I'd also address the use of the same rock tile in a grid across the whole bottom floor area. You do get points for adding some rock objects, but there's no reason you can't mix up the tiles too. The falling over power lines looked nice, as did the blood swamp... could probably do with a few less supports under the structure imo. Decent execution, just maybe the concept isn't as good as it could be.
4) OH GOD. More rockets. Although I'm not a fan, I applaud your intelligent use of them in the first room. Using one launcher to open another is good thinking. The homing saw on top of that seems a little much though... you have me dodging up to three projectiles at the same time in a smallish space.
It can take a little bit to get the floor open if you're not on top of your game, which makes it so frustrating that you will probably instantly die in the next room before you even know what is going on. There's rarely anywhere you can go to get out of the range of the rockets... and I think I've found one, but then the giant saw just runs in after me. I don't think I want to try and finish this one. WAY too many things to manage at once for my brain. Maybe just one rocket launcher on the player at a time would do a lot to help this for me. With all that I'm saying, I hope I'm not coming across as too negative, I definitely don't mean it that way at all. Just giving honest feedback.
5) Pretty colors! I was feeling optimistic about this one until I saw even more rockets... It's a decent enough concept for a level, but isn't it enough to just have to dodge the floating dude and the saws in that small space? I'm not sure how I'm intended to get through this exactly. There's no technique that I learned in the game to mitigate those 3 different types of hazards simultaneously. I tried jumping up high and sliding down, trying to stay low and move in a rhythm, trying to stay in the middle and just wait until I had to move... I like the idea behind this, but right now it's also too frustrating for me.
6) Awesome idea, way too long though. Took me about 20 tries just to get to the third room where I was AGAIN instantly killed by a rocket launcher. Adding a solid platform in the second room where the saw permeable object platform would do a lot to help. If I didn't keep dying early on, my spirit would not have been broken so easily by the rocket at the end. I find that situations that challenge my ability to jump accurately but not when I'm in a rush tend to be the most rewarding for me... your levels all seem to be about putting me out of a comfort zone so you have to hurry and dodge constantly while somehow still staying aware of what is coming up next... although I feel I have a pretty good ability to multi-task, it is lost when I also have to keep time for rhythm (hence why I can't play guitar and sing at the same time). Maybe I'm alone in this though.
The level looked quite nice, but I worry that you'll have to remove some of your light sources. Edmund told me that the rule of thumb is to never go over 2 lights(and the official editor is supposed to cap at 4). I admit I did go over myself in my own chapter, but I learned my lesson after lots of people complained of lag. Hopefully that won't happen here too.
7) Ok, you're going to hate me for this, beautiful level (I can tell you spent a long while working on the details here), great concept... but the platforms are way too fast. There's already a lot going on, so there's no way you're going to be able to calculate all those projectiles and all those platforms while dodging the saws above and below you then
line up a tough jump like that. I do really like this level though, and with some tuning, I'm confident it will be great. Sorry to say the platforms are too fast because I know how many waypoints you're going to need to edit to fix that... :P I've been there myself.
8) This one is worth noting. Visually, very cool with the clouds making a checkerboard pattern in the BG. Then the tangle of power lines in the center is a nice touch also... what's important here I think though, is that you found a better balance of difficulty versus length.
Although I've made my position pretty clear that I'm not a fan of rockets, there is enough going in the players favor that it is tolerable here. There are a couple of key blocks that will at least make for temporary bunkers against the rockets. Then even after you've died a bunch of times figuring out what's going on, you're not upset that it took you 40 seconds each time to die in an instant. I did beat this one, took about 15 lives.
9) Unfortunately you went right back to the old formula in this one. Fans, saws, 8 rocket launchers and salt... I don't see myself ever beating this one. There's too much taking control away from the player and too much forcing me to hurry. I do get that the 6 rocket launchers in a stack were mostly meant to provide an interesting visual effect as you fall though so I guess I'm exaggerating things just a little bit. Visually, this level looks just fine, but it's a bit too much for me.
10) This one is another example of taking the control completely away from the player. There are blocks that vanish in a very important time sequence but you can do nothing about it. There are saws that move in a predetermined path within closed walls and once you're on one side of them, you can do nothing about it. There are rockets that are firing at you while you're trying to comprehend just what you're actually trying to do for a strategy and it's all way too much. There's no real solid way to dodge the rockets consistently since they're usually on both sides and the area is symmetrical. I'd remove about half of the hazards in this level and that might help significantly. It's a shame too cause this one was also very visually interesting. Even the structure of the level could be really capitalized on well if you nail the flow just right.
So out of the 10, I think I actually finished either 3 or 4 of them... Maybe if I kept hammering at them for a really long time I could have figured out more than I did, but I just didn't really feel like if I did win, it was because I mastered the concept at hand, it would usually be a win more by twitch reaction time or dumb luck. I find that a bit counter to what I personally like about SMB. Keeping in mind this work is just following one consistent design ethos and I'm not saying in the least that you're not capable of producing work that would be everything I want it to (and it's just my personal opinion and taste anyway). I can clearly tell you have a knack for design from your work regardless of if I happen to agree with what you set out to accomplish in it.
I hope you don't take any of this criticism the wrong way and I hope there are a few nuggets of info that help you out and are useful to you. If there's anything I can do to help, let me know. You know where to find me!