Limiting the slot game to use for completing the wager is a very sucks rule even though it has fewer wagering requirements since some slot games have a very low RTP and low hit ratio which will burn so much money in able to win. I experience participating in a bonus like this and I didn't do it again because it's very painful to play a slot game that you didn't like while you are already losing a significant percentage of your bankroll even though you are not yet close to completing the wager. Deposit bonus that is free to wager on any game is the best bonus even with slightly high wager volume since some games like Blackjack or Play'n Go slot is very useful to farm wager with minimal risk of losing huge amount.