A Look at a kickstarter for Loka: The world of fantasy chess

I was recently checking out a kickstarter poject for the Loka chess game.  It looks pretty cool for the 50$ Bishop level you get a copy of the game and a couple of extra pieces. This wouldn't be very exciting on its own but should they reach their stretch goal an alternate set of pieces is added to the game.  Rather than having two sets of white and place pieces you end up with two entirely differently functioning sides.

The game seems to have rules beyond the standard chess board.  Allowing for you to play three queens or several pawns, or so says the kickstarter page.  I am guessing the armies will probably have their own rules as well.  The two mentioned are fire and earth, but as stated above earth only gets unlocked if they reach a stretch goal.

That is sort of a funny way to do the project as I wonder if they create an artificial speed bump for themselves.  They are at 45,000 of the 50,000 they need to hit that stretch goal so should make it in the time they have left.  But for me I feel my self less inclined to fund until after I see that goal met.  I wonder if they are creating a rollercoaster of funding.  When they finally hit that stretch goal having a bunch of folks jump in now that the pot has been sweetened.   I wonder if that is for the best?

And if anyone can answer this it would be great.  Can you alter stretch goals after a kickstarter has begun.  So say in the case of Loka , deciding their product is better with the fire and earth sets.  Could they just roll the stretch goal into the product offering?  basically allowing the kickstarter to eliminate the speed bump they created?  I am asking more for personal knowledge of how kickstarter works.

UPDATE:  It looks like the earth set is unlocked and they have set fairly easy stretch goals for an air set which will more than likely unlock.  There is some way to go for an Ice set but looks very reachable.  These make the hundred dollar pledge level very attractive.  I am not sure if you get to pick what you get on the 50$ pledge level.  There is another goal point for an upgraded board which should kick in for the 50$ level.  Looks like this kickstarter has hit its stride now and is giving a nice set of rewards. 

It does make me wonder can you add to your funding and go from one level to another?  Does Kickstarter keep track.  Here if I had kicked in 50 I would really consider kicking in another 50 for the 100 dollar level.