Hydorah is a horizontally scrolling shooter that was published on 03/06/2010 for Windows and has taken a lot of inspiration from many well known shumps including Gradius, R-Type, Space Manbow, and Enforcer to name a few. The creator who goes by Locomalito, emphasizes that the Hydorah has that "old school style" to it in both graphics and gameplay. The music and graphics were created by Gryzor87.
From the manual
Everything began when a terrible ambush took us by surprise and destroyed our army, leaving no strike back option against the Meroptian Base. At this point, individual assault and combat planes was the only choice. The squadron members were ready for the impossible, but the worst was yet to come...
The stages are not completely linear in that there are two small branches that occur on the map, although ultimately the last stages are the same.
The stages are generally large and the player can scroll up and down them to some extent. Within the stages there are secret items that can be collected which if all are, something becomes unlocked.
Upon beating a stage, the player will earn a new weapon. Primary, Secondary, and Bomb weapons can be equipped at the beginning of each stage. As the player gathers weapon powerups, their current weapon that the icon is for (Primary, Secondary) will be upgraded to a max of 10 where the weapon will gain an added feature. There are also icons for speedup, shield, and additional bombs. There are five of each type of weapon, for a total of 15 overall.
Enemies come in many varieties from the standard fighters to huge semi-tank mechs to organic creatures. As noted before, the Hydorah is meant to give a challenging and memorable experience as the traditional shmup classics did.