What is the Cowboy with a Gatling Gun Demo game, how does it work?

According to the introduction of Grant Ojanen's Creations, Cowboy with a Gatling Gun Demo is a Arcade game on the Android platform. There is currently a na version released on Feb 25, 2020, you can see the details below.

Play as Poncho Pat the meanest outlaw in the west. Shoot down other outlaws with his mini gun. You can ride Poncho Pat's horse while you blast baddies. You can buy horses and gun upgrades in Scruffy's store. The game has old school old school style graphics and full voice acting.

Full Game Features
✪ Upgrade your guns and buy new horses in Scruffy's store
✪ Export/import save progress (Android 4.4+)
✪ Goofy one liner voice acting
✪ 7 episodes in western locations
✪ Art gallery
✪ In-game achievements

Full Game Link
https://play.google.com/store/apps/details?id=com.grantsgames.Cowboy_with_a_Gatling_Gun

More Details
Offline: Yes
Lightweight: less than 15MB
Input Methods: touch, mouse, gamepad
Categories: shooter
Themes: pixel, 2d, retro, western
Players: singleplayer
Export/Import Save: Yes
Save Files: 1

What's new in version na • game over screen no longer exits on a timer
• hint about gun upgrades on game over screen
• small compatibility improvements
• a few bug fixes
• many small improvements