Bitcoin Blast is one of five apps made by Bling. It's level passing game but you don't have to win level to be rewarded, just complete it. You can withdraw your points once a week to your Coinbase wallet so make it count. If you want you can download all 5 apps and earnings from them will be merged. You can play 10 matches daily by one app so if you have all 5 apps you can earn about 5milion points. You can see convert rate on screenshot bellow, and don't worry, it's legit but you won't get rich with it, at this point i have 0,85€ in BTC earned by these apps