Hydorah is a nonlinear classic smashup with a large library of levels and enemies influenced by Gradius, R-Type, Darius and other classics.

There is a single difficulty level, based on the 80s standards, that requires mastering in order to progress. Graphics are simple enough to not interfere with the gameplay, while they're polished to show the unique personality of each level. It has a huge soundtrack composed exclusively by Gryzor87, who has not hesitated in taking legendary synthesizers to create retro futuristic, powerful and sometimes dark themes. Every track has been designed to fit each level like a glove.

The games was influenced by Gradius, R-Type and Darius as well as other lesser known classics like Turrican, Enforcer, Space Manbow, Hellfire, X-Multiply, Guardian, Hydefos, Armalyte and more.