Vaccine Case is a brilliant, original, FUN, puzzle by Wataru Nakano.
The object is to kill the viruses with the matching gases by opening and closing doors. When the virus is killed, the gas will disappear from that room Therefore, you may need to save some gas for down the road.
Previously, I reviewed the Lite version which has 12 levels. The paid version is $2.99 with 100 levels. Well worth the money.
Right now I’ve solved about 97 of the levels. Brilliant and fun. Easily one of the Best Puzzle App Games ever.