This is a paid asset, but now you can download Shmup Boss Free.
Detail this asset from Unity Store: Original Link
Shmup Boss v2.01 (Latest version)
Because You Are the Boss!
Shmup Boss shoot ’em up game genre template.
Shmup Boss provides an excellent foundation for creating any scrolling shooter games. If you are new to Unity this will give you an easy way to create your own levels, and if you are an experienced guru this will jump start your development and provide a basis for your shmup games.
-Mobile & desktop support.
-Horizontal & vertical scrolling levels.
-Finite & infinite level creator.
-Background layering system.
-Global difficulty system.
-Main menu with settings and a player select option.
-In level UI.
-Well documented and commented modular code.
-Player upgrades and pickups
-Multi phased boss system.
-Multiple enemy mover types and spawning options.
-Event driven actions.
-Pooled bullets and missiles munition weapons system.
-Particle weapons system.
-Radial shooting and timed rate controller.
-Fire and hit FX.
-5 Original soundtracks and SFX samples
-Animated 2D effects.
-All demos you see in the trailer are included in the pack.
-URP & HDRP compatible.
-While Shmup Boss provides an array of features, Shmup games are a huge genre and we did not implement every possible feature, please check the support thread to download the documentation, view the tutorials or ask any questions before making your purchase.
-Camera is orthographic and you cannot use a perspective camera.