This is my first time seeing a review by this user (PSVRWorld). I kinda like the uniqueness of the brand being established here.
As for the game, I beat the single player campaign back when it was first released on the Oculus Rift. I've also spent quite a bit of time with Space Pirate Trainer, which received a lot of praise (and is a similar game).
In my opinion, VR Invaders is an extremely well done shooter, and I prefer it 100% over Space Pirate Trainer. The immersion on the Rift is top notch, and the 3D sound didn't seem to be a problem there. Often times I felt like I was going to fall off the platform when things got hectic; that was exciting!
My favorite strategy was to look in one direction to shoot, while using my shield to block areas behind me (and completely out of my line-of-sight). It works perfectly, which speaks highly of the developers to allow off-camera action to take place successfully.
As far as stationary shooters go, I would give this game an 8 out of 10.