I think this is a really awesome collection, I do love how it has so many different games and different version of each, if you want to see my opinion on each game, I have them all the links to each are below. My favorite has to be Operation C.

Contra (Arcade)
https://www.backloggd.com/u/TerraGlaive/review/689089/

Super Contra (Arcade)
https://www.backloggd.com/u/TerraGlaive/review/694237/

Contra (NES)
https://www.backloggd.com/u/TerraGlaive/review/751607/

Contra (FAMICOM)
https://www.backloggd.com/u/TerraGlaive/review/751610/

Super C (NES)
https://www.backloggd.com/u/TerraGlaive/review/751615/

Operation C (GB)
https://www.backloggd.com/u/TerraGlaive/review/751620/

Contra III: the Alien Wars (SNES)
https://www.backloggd.com/u/TerraGlaive/review/751626/

Super Probotector: Alien Rebels (SNES)
https://www.backloggd.com/u/TerraGlaive/review/751627/

Contra: Hard Corps (GEN)
https://www.backloggd.com/u/TerraGlaive/review/751634/

Probotector (GEN)
https://www.backloggd.com/u/TerraGlaive/review/751638/