Giving something special to the 20$ tier. (Patreon)

I'm considering adding something special for the $20 tier since they currently don't have any perks.
My idea is to add a playtesting to the $20 tier. I'd like to hear your thoughts on this.

Keep in mind that it's a playtest version, meaning it will be insanely buggy and things will be missing. So, please don't think of it as a 'play earlier tier.'