The crawling aliens that have made their appearance in the previous Contra games are obviously inspirted by the facehuggers from the Alien movie series. The last level of Operation C pays further homage to Aliens by having the creatures explode out of large test tubes similar to those found in the laboratory.

At the end of the game, you fight the "true" final battle, navigate through a small corridor and must shoot at the core, which is unprotected. This is very similar to Konami's earlier Gradius games, where the final boss (usually a heart or a giant head) would be mostly helpless, waiting for you to destroy it.