Woah thanks!Usually extracting the game apk will tell you what engine it utilizes. I'll do a simple showcase for the game you specified. If we extract the apk and browse to its sub-folders; META-INF -> MANIFEST.MF, that will let you know what game engine it is running on:
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There are of course different ways to check, but this is the easiest & quickest method. Other method, while not popular, the game devs will give credits to the engine they're utilizing on the initial menu, with the words "Powered by Unity" or "Made with Unity" followed by product logo.