The base concept for this game with the theme was one of the more interesting approaches at the "have more of _, lose speed" mechanic that seems to be showing up.  Since most of those games have a button, like yours, to remove or lose the item but they don't really have a downside to it.  If you remove or lose the item it's basically just a perk cause you negate the downside completely.  Whereas here you literally trade lives for speed.  A few finer points of feedback though:

• The ragdoll seems interesting, and could lead to some quality rage moments.  Though some of the movement on it seems weird, specifically the jumping in certain areas compared to others etc.  It seems, and I'm not sure if this is intended, that there is also a way you can "grab" walls, I'm assuming using the ragdoll physics, which ended up being useful, and could possibly be applied as a mechanic.  
• The hearts removal mechanic was a bit weird, due to the abundance of the hearts in the particles I thought I was losing way more than I actually did.  So maybe adding a specific particle that has a -1/+1 on pickup and on loss could help?
• The levels and their checkpoints were kinda annoying since you were forced through a series of levels everytime you died on a later one in the segment.  It sort of fits the hearts theme, though it did get relatively annoying, especially with the fact that the ragdoll made some movements imprecise and the jumps being weird contributed to a lot of deaths from random over or under jumps.  
• The design of the levels themselves got pretty interesting, specifically in segment 2 where there was a decent amount of variation thrown in, though without too much of a difficulty curve when throwing in the tipping platforms and the tiny boxes as well as the spinning platforms.  Some of it definitely needed some tweaking though to make it easier to find the exit.

With a bit of tweaking on the movement mechanics to make them a bit more precise, which is a little hard to do I expect with ragdolls thrown in, this games concept along with the level design could be pretty interesting.  

I like this game! Great gameplay! Good job!

Please check my game as well ;)