It is exactly what it looks like, alien blasting, with ads. Ads to recharge, ads for another life, ads after mission is over. But, given the cost (free) I don’t mind the ads terribly. Good variety weapons, and fun alien blasting.An update in early March 2018, however, completely nerfed the game. There are now “gems” for some unexplained purpose - no explanations - they just appeared. And ship powers and upgrades were dramatically downgraded for regular gameplay, and upgraded for “endless” levels. So if you play “endless” mode, you are close to invincible - before the update my best endless was about lvl 125 and I worked hard to get there. After the March update, the game crashed when I was like level 723 and I was never really challenged. Meanwhile, in the main game, my ships which had been previously upgraded a lot, were way way weaker, or the enemies were way way stronger - like the weakest enemies I could kill in 1 shot previously took 3 and 4hits to kill after the update. And, the enemies move WAY faster than before - not just like twice as fast, but more like 10x. The update makes it feel like I lost a huge amount of the progress/upgrades I had received and just completely changes gameplay from before. Now, the game is free, so I didn’t lose any $$, but I definitely lost progress. Before the update I would have rated the game a 4, with the update, I feel so much further behind I cannot rate it higher than a 2 and will likely delete it.