3 stars: Fun till you get everything researched and through lvl 50 with 5 stars. Then you have challenges, but some (like lvl 32 hard) require one of the purchased heroes. I actually did buy 1 of the heroes, but each hero is $10. I'm not spending more than the $10 I already spent just to beat a few challenge levels. At some point, it just becomes frustrating to not beat a lvl when you have 2 heroes and 100% research. Uninstalled.
5 stars: Great game, good time killer so be warned. Only pay to play requirements are for heroes. I still have not seen any way to acquire the better ones for free. That said, they are available for a reasonable price and are often sold in bundle packages with other items.
3 stars: I liked the game but I just got bored playing with just one hero. Getting second hero is quite difficult or impossible or one has to pay for that. Developer should think about providing that to make it more interesting. Thanks!
3 stars: One of the best in its category. I played it a few years ago and back then the game was 5 stars, because was game experience over money. Now that I returned, the game change too much to money over game experience...
4 stars: The game is so addictive, but with out buying another hero with real money, it is almost impossible to move forward with the Flak, after certain point. Also I think in-app purchases are expensive, we need buy each hero seperately, can't use the gems or game coins. I bought Surge to support the game and t...