All icons come from Open Game Art (art by onyum.com, comissionned by Bart Kelsey)
released under CC-BY-SA 3+
* options_players & random_kart were tweaked by Marianne Gagnon


Except :
main_*.png icons, hourglass, back, back_addons, next_addons, package.png
    released under Creative-Commons BY-SA 3, By yeKcim (Anthony Carré)

mode_tt, released under Creative-Commons BY-SA 3, incorporatings artwork from yeKcim and onyum.com,
         modified by Totoplus62

mode_easter, mode_ftl, mode_soccer, mode_normal, race_giveup: by Totoplus62, released under CC-BY-SA 3.0

soccer balls released under CC-BY-SA 3.0 by Néd J. Édoire

tutorial.png    by Totoplus62, released under CC-BY-SA 3.0

Logo and Logo_slim : under CC-BY-SA 3.0+ by 'rastapax'

difficulty_*.png icons, released under Creative-Commons BY-SA 3, By Conso (Constantin Pelikan)

title_font, by Marianne Gagnon (Auria), released under CC-BY-SA 3+

screen*.png, by Marianne Gagnon (Auria), including elements from the public domain Tango icon set

speed.png by Alayan, with elements by Totoplus62, released under CC-BY-SA 3

speed*.png by Alayan, released under CC-0

gauge*.png by Alayan, released under CC-0

menu_story by tavariz91, released under CC-0

mass.png by Auria, released under CC-0

power.png by Auria, based on https://openclipart.org/detail/193925/check-engine and https://openclipart.org/detail/144799/power-icon, released under CC-0

crown.png by glitch, from https://openclipart.org/detail/210257/misc-game-crown, released under public domain

ghost_plus.png by Alayan, based on https://openclipart.org/detail/17847/cartoon-ghost by lemmling, released under CC-O

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Glass Skin by Auria, under CC-BY-SA 3+
except background, under CC-BY-SA, by 'elisee'