Perhaps the $20 minimum deposit is for the 100FS only while the 500% deposit bonus is something different or not a part of the exclusive bitcointalk promo since it is available for global users.
Means that if you want to get both (100FS + 500% bonus) then you will need to deposit at least $50 but if you deposit $20, you will get the 100FS only.
Just guessing ofc since the answer from OP is not really clear since I guess he just copied the general terms of the bonuses.
Yeah, that's possible but at 20 bucks, regular bonus may be better since you get 200 free spins instead of 100 unless the bet is boosted. I think I've seen casinos with 30 bucks minimum for their deposit bonus as well though it's not 500% boosted but still better than free spins imo since we could pick other games.
It would be nice if the exclusive bitcointalk promo would be different as oppose to regular one otherwise it feels a bit gimmicky.