4 stars: It's fun for the first hour or two, but then the bosses get too unpredictable and impossible to defeat without purchasing upgrades. Along the way, you need to figure out which ads are worth watching since there's an offer every three minutes. I don't understand 90% of the rest of the money sucking icons on the screen. It's a mine field. I'm uninstalling at this point.
5 stars: I honestly think this is a pretty great phone game. You can invest what you want into the game. There aren't any forced ads between levels but can instead be chosen for extra rewards which isnt too bad at all especially a new ship. Just watch an ad or two per day and it honestly remains a very fun game. I particularly enjoy the boss fights, however find some to be almost like Dark Souls bosses; requiring my full attention to complete.
3 stars: An OK game. You have to watch ads in order to get extra spins on the wheel or extra items or extra play time. If you want to level up you'll have to either watch ads or buy equipment. Just Realized I would need to complete 50 more nearly impossible levels at the equipment level I currently have to get the next major upgrade. I'm going to go find myself another game.
3 stars: Base game - super fun. Everything else is money-grab by developers. They say you dont have to pay - it's like saying that you can watch the Fellowship of the Ring but not 2 Towers and ROTK. Im a month into it - still dont know how to use half of the stuff, everything lacks...