Of course, the primal intention of many fresh game developers is to create a first-person shooter. This is a good dream, but a very bad idea. A competitive modern FPS, even if it is going to be developed for handheld devices, requires titanic efforts, that is, a gigantic job that will be enormous for small teams. There should be an original concept that can attract the attention of the audience: a good story, tons of accurate 3D models and textures, great animation, perfect special effects, optimized graphics, minimum glitches, and an ideal balance in a new, competitive FPS. Don't forget the hundreds of hidden nuances and pitfalls.
It is more reasonable to reduce our ambitions a little bit and start with a smaller project to experiment with. It is good to take some ideas from the good old arcades. For example, the Shoot 'em up subgenre, where a character is surrounded with lots of enemies and needs to hold fire all the time, is the mechanics from Space Invaders. The...