I don't know if this game is worth developing, i'm making another game, so should i finish Si Space first and then develop that other game

or just abandon si space?

https://sickdot.itch.io/si-space

I just had a quick go on it and it has a nice style already, runs quite smooth and could be good. Tbh I think its worth finishing the game even if you just fill it out with a menu/tutorial hints etc, just so you have another finished game in your portfolio.

The gameplay and art is already there, id say make it a cut down version of your original plans but still finish it as a mini game.
Up to you though!

My advice would be if you enjoy playing the game finish it. I have abandoned a few projects because, having worked hard on them, I have decided that I am not enjoying playing them. My attitude is that if I'm not enjoying it why would other people?

I finished the game, https://sickdot.itch.io/si-space, watch the trailer if you want to :)