Great Job!!
I have to take it down 2 points though because of a few things... nah I changed my mind I'll make it one.
1. The Confetti Bomb I felt wasn't colorful enough to look like confetti, so maybe if you made the bomb pink with, say, blue-and-green confetti, it might be more kid-friendly.
2. The difficulty "slant" was very nice, in fact I almost want to say perfect except where there is one of the early levels where 3 guards are coming at you at once, I just barely made it out by placing a bomb to make the guards fall then quickly walking over them. If you could re-position the guards in those places that would be nice.
3. This is a lot more minor but as an experienced gamer I was able to easily overcome this but the speed of the guards should be slower to be more kid-friendly, but again this is more minor.
4. I wish I had known before I had played that I could jump with Shift, because the game doesn't mention it at all even though I didn't have a single problem with any of the levels without it; it just would have been a lot easier.
5. I think this may be the biggest OR the smallest problem of them all, but most of the Guards could not climb down ladders and that made it too easy to avoid them; I noticed this particularly on the pirate ship level where the guard went up the ladder, got stuck, but instead of climbing back down just sorta walked in place. Maybe it's only specific guards, because I could have sworn using them before.
6. Now that I notice it, THIS is the most minor one of them all, but I should still mention (although you probably already know) and that is the slanted floors. Maybe they actually were just there for decoration but I could walk through them just as easily as if they weren't there.
Now even with these (holy cow I can't believe there were this many) 6 semi-major issues, you can still see that it only took 1 point off, and I shouldn't even be taking it off, either. But seriously, you did a great job with this game and i want to congratulate you on your effort. There were a LOT of levels it seemed so there was no way kids would get bored (although they may get tired lol). All in all this is probably the best kiddy-platformer of all time and I think any little kid who is just old enough to understand at be somewhat good at this would easily get hooked on video games, so thanks for stealing one more kid from the outdoors (JUST TEASING ^_^)!!!
Summary: It was great, despite few flaws, and it served it's purpose almost better than most other things I've seen, so it deserves a 9/10.