Wings of Ge.Ne.Sis
Control your character with the mouse, pointing where you want to go. Fire with the left mouse button, or just tap [A] to turn on autofire and make your life much easier.  changes between your two weapons (generally a ranged attack and a melee attack),  uses your mount's high-powered special attack, and  through  use helpful items that you equip before each stage. As you shoot down enemies, you earn two types of currency to purchase items and feed your mount. You also earn experience points and can develop your character as you'd like.
You can choose between the three titular characters at the start of the game. Gelyan has high endurance, earns extra attribute points every so often and has a protective shell for reducing damage. Neraine has high agility and an increased dodge rate, often avoiding damage from what would otherwise be a direct hit and striking back with a powerful counterattack. Sisily has high empathy and her mounts are more powerful, plus she can fire a special beam attack. All the characters are fairly balanced, though Neraine is probably the best all-around choice thanks to her increased dodge rate and resultant longevity.
Wings of Ge.Ne.Sis is certainly an unusual spinoff. One might have expected another RPG, especially after how excellent the original game was, but Wings still manages to stand out amongst its shooter contemporaries.
Analysis: There's an immense depth of gameplay here that's unusual for a side-scrolling shooter. You can upgrade your character in a variety of ways, including their attributes, equipment and mount. You can feed your mount either variety of currency and it will evolve based on its diet, but you might want to save some for the shop as well. While it's probably possible to get through the game without customizing or upgrading by using raw twitch shooter skills, you'd be missing out on a big part of the fun.
Wings of Ge.Ne.Sis uses the same art style as the original RPG. It's a surreal aesthetic, appropriate for a game that takes place in a dreamscape. Everything is beautifully animated and it's generally easy to see what's going on even when things get hectic.
The only real flaw in the game is the lack of keyboard control. Mouse control is highly imprecise, especially if you're using a touchpad, so expect some cheap hits. Thankfully the game is fairly forgiving and it's possible to build your character's agility or endurance if you're taking too much damage.
Likewise, while the game's various bosses can be tough, playing toward your character's strengths will usually see you through. The bosses do have a tendency to flood the screen with difficult-to-avoid projectiles, but since you generally won't die in a single hit it's not a massive problem. Practice, as always, makes perfect, plus you earn experience even after being killed.
All in all, Wings of Ge.Ne.Sis is a great choice for shooter fans. The depth and customization on display here make it unique amongst shooters. Even those who aren't necessarily shooter fans but loved the art style and writing of the original game will find something to enjoy here.