This pack includes a custom coin and a block that will change its behavior once a certain amount of the custom coins is collected. By default, the amount is 30, and the block will turn from solid (130) to unsolid (25). This block is very customizable, though!
I recommend you to read the included Readme to help you set everything up. It's not as complicated as it seems.
Credit is not necessary, but it would be appreciated, as I spent a long time and effort coding those blocks. I hope you'll make a good use of them!
This version adds ExAnimation support of some sort and fixes some weird typos in the files.