Actually, it's from $10, although you need to pay for the game later. Some people seem to be misunderstanding. Read the description of $25 tier at
this page. Simply, $25 tier is an early bird edition. So, I'd say, grab the $25 tier since there difference is just the price - reward is the same. This is due to the restriction of the Kickstarter site which prevents existing reward tiers from being edited by the creators (This is why I recommended you to read the official site).