I would treat your first game more as a learning experience. That’s at least how I approach it. There is a lot you need to learn. Same goes for making a game more commercial (something I don’t really have to worry about). I can imagine a platformer (especially a metroidvania type of platformer), would have a larger audience then a shmup. Shmups have become quite a niche these days. The last one I have played was probably Jets ‘n Guns, which is easily 13+ years ago.

The new project is looking good!