Open channel3.gg in Chrome. Click the Install icon in the right side of the address bar:
Click Install when you get this prompt.
After installation, you can pin to the Windows taskbar alongside your other favorite apps.
Open channel3.gg in Safari. It has to be Safari.
Tap the Share button in the middle of the footer.
Tap Add to Home Screen.
Tap Add on the prompt.
BOOM. You're done. iPhones try to act like it's "just a website bookmark" because they want everyone to go through the App Store but really it functions just like an app... Full screen, moveable icon on your home screen. All of it.
Enjoy.
Install the Channel 3 app from the Google Play Store.
Compared to the few other Atara games I've tried (which have primarily been shoot things as they descend from the top of the screen), this game has a lot more freedom of movement.
I was confused at first by what my objective was - I thought it was simply kill as many fish as possible. But rather you have to descend to the bottom, grab treasure, and then get back to the top where a mermaid then takes you to an increasingly difficult level. You actually don't have to shoot fish (in fact doing so results in a faster version taking its place that's harder to hit) and it's probably better not to.
So while it seems better than the few other Atara games I've played, it's still not any good by today's standards (unless perhaps you played and enjoyed it when it first came out).