Hydorah is an original side-scrolling shooter with authentic 80's arcade-style gameplay. The high-res text is about the only hint that you aren't playing an arcade ROM. Locomalito did a superb job capturing the look and feel of the arcade, right down to the boot-up ROM check and cheesy dialogue.
Ships are customizable and can be outfitted with parts that you earn in play. If you explore areas that are hard to reach, you may find hidden bonuses.
Unfortunately, like an arcade game, Hydorah has only one difficulty setting -- extra hard. Unless you have played lots of shmups, you will have hard time passing the first level. Furthermore there's no mercy for the hapless. For instance, twin lasers are earned on the way to a boss battle. If, in the boss battle, you blow up and then restart it, you lose your twin lasers, making it even harder to beat the boss. Limited save points make Hydorah more difficult, and potentially tediously repetitive.
Overall Hydorah is a high-quality, polished shooter that is designed for one audience: hardcore shmup fans.