I like the secrets in the second game (the easy way medal [smiley face emoji])and it just over all looks better than the third one, its a pretty good nice job with it but i think ill go back to the first one. In the fourth one, you should make it like the second but bigger, with more upgrades, the black market should stay the same as well just with more. (I love the omega stuff, that was a good idea) Last but not least, the ios version of the second game, i dont like how different it is to the original.