After going through the toybox, here were my experiences about it:
The first thing that struck me as odd was how there was no ledge-grab. So many of my jumps felt like they barely made it and I was struggling to hover against the ledge but was a hair too low to get on top of it, I didn't realize how to reach most of the areas until I found out about the spring-jump.... which leads me to my next point.
The spring jump felt massively over-utilized. It pretty much completely renders the standard single and double-jump moot, at least half if not more of the areas felt like they could only be reached with it, and there was no reason not to use it in place of a standard jump, I was just using it everywhere and practically forgot about the standard jump, in fact, I was pretty much completely able to bypass that sea-saw area ( http://i.imgur.com/das4hQJ.jpg
) by standing on the middle and spring-jumping to avoid several of them. It nearly surprised me when I re-visited some areas and was able to reach those with a standard double-jump. On top of this, using it in motion felt odd. The way the animation plays, it feels like something meant to be used when you are stationary, but you can use it while in motion and you even continue moving a little bit while using it. The animation and point of the move don't seem to match up with being able to use it while moving.
Although, what I did like about the spring-jump is that holding A immediately puts you into slide at the end of the jump so you don't have to time it manually, holding A on the double-jump seems to do this too, though not on a single jump.
I also found it helpful how you could do your second jump or glide while falling. Most games, only let you do the second jump and/or slide at the apex of your jump, not once you have started descending.
I understand that the ToyBox is practically a "debug view" and that you can easily tell which ledge will make you slide simply because it's blue, but some of them felt too shallow to be sliding on. E.G. That small pyramid near the stone arches, the angle is so shallow and the ledge itself barely taller than Yooka that it felt like I should be able to run on it, but you instantly slide as soon as you come into contact.
Speaking of which, while I know the whole point of the sliding is the game basically telling you "No, you can't just run up here, find a different way to get back", it feels like you have a bit too little control during sliding, namely, how you can't jump while sliding.
Also while I am on the subject of sliding and ledges, it felt a bit too easy to go up a ledge too, you just have to be rolling, wouldn't you need to build momentum for some of them first?
And speaking of rolling, it felt difficult to transition to a jump/glide from a roll. You can jump while rolling, but it didn't seem like the game was designed to quickly let you stop rolling and go into a jump/glide, I just wound up hopping a little while the rolling animation ended whenever I tried.
Come to think of it, movement underwater felt a little rough as well, there was a lot of drag causing you to turn very slow.
It was very hard to tell if there was anything behind the vertical glass walls, I don't know if this was intentional, but the effect the walls use distorts what is behind them so much that until I stood still and tried to focus on what was behind them, I couldn't even tell anything was behind them at all, much less WHAT was behind them.
Also, while we are on the subject of visuals, the shadows confused me too. Took me a little bit to realize that the game had two shadows, and only one relates to where you will land when you drop down, I had a few falls because of thinking the non-drop shadow was where I would land.
Some other things I ran into:
Camera is easy to get stuck behind walls, especially if there are a bunch of towers or narrow ledges around you, this can be annoying when the camera winds up facing you and you want to turn it around. Such as here: http://i.imgur.com/1itCu1P.jpg
It felt difficult to push objects correctly with the way the physics engine works, it took a few tries in that glass-ceiling area to get the game to recognize I was trying to push something and actually move it, and in others like near that sea-saw area, it was near impossible to move stuff where I wanted to.
The physics for movable objects also feel very floaty, the objects themselves act like they have no weight to them and are very easy to flip over or turn at an angle when you wanted to push it straight.
Come to think of it, some of the debris landed standing vertically against a wall, acting like a platform. I am not sure if this is the right kind of physics engine for this game, it seems a bit too "realistic" for the rest of the cartoony nature of this game. I was expecting the boxes and barrels to shatter with parts falling all over the place when I broke them, not just... slightly fall apart in place with half their pieces leaning against walls.
At a few points the collision detection on the sea-saws failed and I fell through them.
This texture was pretty pixelated up-close: http://i.imgur.com/QVgAV4M.jpg