I think a space shoot em up game using the touchscreen with 2+ fingers might be fun and different than most normal twin stick shooter.
I’ve worked up a super WIP game using love2d where you use one finger to move the ship, and a second to move the target around. As long as both fingers are down, your ship will shoot and constantly rotates to point at the crosshair. Check out the project on github.
After I got the bullets working, I added some basic plane graphics as placeholders for bad guys. They don’t do anything yet, but everything is using the love2d physics system for collisions and motion, so the planes can be bounced around and it’s kind of fun.
I couldn’t get the bullets to shoot right at first, but with physics enabled the result was funny. They came out the wrong end of the ship and didn’t move very fast but could be pushed around.