The idea could work, but I feel like the possibilities offered don't feel very cool and unique, but are feel a bit too cheap/artificial (moving projectile, creating a barrier). I would have expected things like choosing 2 areas to transfer projectiles entering 1 area to the other, or things like this.

It's also too bad there's no mechanic to deal with enemy ships. I tried moving their projectiles behind them or things like that, or using the gravity well to attract the ships, but nothing worked.

The gravity well and barrier can work well together (cool to start to have some sort of combo thing), as you can attract and kill lots of bullets with this. Moving projectiles one by one is quite painful from my experience, so I didn't do it a lot, and it seems to go a little bit against your game (hellbullet ! tons of bullets ! precisely moving 1 bullet at a time ?).