Credits:

Soldiers: https://al-core.itch.io/sci-fi-animated-army-squad

UI elements: https://bdragon1727.itch.io/basic-pixel-health-bar-and-scroll-bar

Font: https://caffinate.itch.io/abaddon

Airship model: https://assetstore.unity.com/packages/3d/vehicles/space/free-sf-fighter-11711

Sound effects: https://shapeforms.itch.io/shapeforms-audio-free-sfx

Music: Nerves - https://incompetech.com/music/royalty-free/music.html

Tileset: https://craftpix.net/freebies/free-village-pixel-tileset-for-top-down-defense/

Ruins: https://craftpix.net/freebies/free-top-down-ruins-pixel-art/