The game is a cross between the binding of isaac and nuclear throne, with sprinkles of originality tossed in.
The game showcases how to use/create a shooting mechanic, upgrades, enemies with varying AI and attack patterns, leaderboards, health bars and other UI elements, multiple scenes, and external events.
The mobile version also demonstrates how to create dual joysticks using the multitouch joystick extension.
Check out the YouTube video explaining how this example was made.
How it's built?
This game is made with GDevelop using these features: