It was a guy on a hill 16bit style and you just shoot these monsters, you could charge the gun and shoot a big energy ball, super simple game.
I'm assuming it was pulled from the App Store. It should still be in your purchase list if you bought it.
Luckily this game has transferred from phone to phone from iCloud backups. I'm surprised it never got updated. One of the best!
Here's another to rack the brains of TA forums. A game that you could flick this sort of ball thing up and up via elastic banded poles. It had a sort of Japanese theme. And there's a water escalating. It's an old one going back 2009 or 2010. (Lol just thought can probably find out answer to this on old iPod touch, but here's conundrum in meantime)
I had Ziggurat installed on my phone, from several upgrades and backups, but it doesn't seem to run on my iPhone 6, 9.x so I ended up uninstalling it. It was a fun game, though.