Remember the old Chex Quest game in 1996 by Digital Café as a Chex cereal promotion? I don't, but I remember reading about it. This was an attempt to create a non-violent first person shooter for kids age 6-9 where you can shoot slimy aliens who are trying to take your Chex cereal away.



Team Chex Quest HD have re-created the original game in a modern game engine and its totally free!
https://store.steampowered.com/app/804270/Chex_Quest_HD/

Slay green slime aliens with your special laser weapons and even a spoon. Find the keys and navigate your way through the levels leaving no alien traces behind. There are secret areas, interactive elements and of course a non violent arsenal of cereal weapons.

Proton handled Chex Quest just fine in Steam. I was able to download, launch and play several levels without any bugs or artifacts.

Specs:
Mint 19.3 64-bit
GeForce GTX 1060
Nvidia 440.100
Proton 5.0-9