How many people worked on this game total?
1

Did you use any existing assets? If so, list them below.
Yes, a significant number of graphics and sound assets. From: Kenney (Kenney.nl), for his countless free assets, including sprites, sounds and fonts used all over this game! Itch.io for making all this possible, including sharing a large asset library. Thank you to Robert Brooks aka gamedeveloperstudio for a number of beautiful sprites, including the aircraft; and to Vnitti for the pretty parallax background images. Nicolae (Xelu) Berbece of "Those Awesome Guys" for some really professional keyboard and mouse images. OpenGameArt for sharing a wealth of freely available resources. Thank you to Vasiliy Edomin for making and sharing the beautiful yellow helicopter that is this game's main character. Unity Technologies, who puts out a lot of free assets in addition to the free (with conditions) and still awesome game engine! Sonniss Professional Sound Libraries compiles a huge bundle of freely usable sound samples for GDC where many different sound studios provide quality content. Thank you to them and to SoundMorph, GameMaster Audio, Shapeforms Audio and BluezoneCorp for sharing quality audio files. Gregor Quendel's nice music clips provide the music for the game ("Cinematic Trailer Music - Collection" at Unity Asset Store). FreeSound for being a great resource for sound effects. Thank you to Kyles and Antumdeluge. Filmcow for providing a big library of recorded and processed sounds of really good quality. Pixabay, mostly known for their large collection of freely downloadable photographs, for also having a sizable sound library. Thank you for a number of explosion sounds (no username was available).