Voting low for this one, I'm afraid. I have several points of issue. Disclosure, I only managed to finish up to level six.
1. We don't have the ability to aim. However, our enemies do, and so we are forced to hover in front of them, constantly pressing the up arrow key at a constant pace in order to avoid getting shot at and/or hit them in the first place. How much of a problem would it be to make it so that we could aim and fire with the mouse?
2. The remote grenade. It is still a grenade, but it explodes at a set timer, like any other grenade. Given this, why is it called a remote grenade? Why not just "grenade launcher?" I can't comment on the other weapons (besides the basic one) since I didn't manage to get enough money to buy them.
Also, if the enemy happens to shoot it (say, because you're firing it at a turret) it goes and flies towards you. So what we have is a grenade that we have no control over once it leaves the gun, that bounces everywhere. Were I the person in charge of whoever's in control of the robot, the idiot who designed that thing should be fired with extreme prejudice; I don't want a weapon that has a nasty habit of exploding next to my soldiers (even if they are easily replaceable robots).
3. It seems to be very difficult to obtain as much cash as we could previously, though that may just be me. I don't think it is, though, since there are fewer enemies for each level, and fewer (it seems) boxes. Also, it's a bit harder to catch a flying orb than it is to run over to a gold bar. I can understand why the gold bars could be problematic (they'd sometimes land on lasers), but this could be fixed by having them be collectable by hitting them with the quantum tether. Which gets me into my final point.
4. This is a downgrade from the previous game. It's clear that you reused models, coding, et cetera. So why can't we do as much? We don't have the quantum tether, we have these weird flying orb things to collect for cash (and they seem to vanish more quickly than the gold bars), we can't aim, our remote grenade can't be detonated with a mouse click... all this was in the previous game. So why was it all removed from this game?
Things like not being able to aim, and the remote grenade issue, would be far more acceptable (though still problems) if I hadn't seen Quantum Patrol include them. Quantum Patrol 2 doesn't, and I can't see why it doesn't. Heck, you even have a boost bar included, despite (in the levels I played) there being... nothing filling it. Ever. You can fly as long as you want, which is nice I guess, but it means that you have a superfluous part of your GUI--and it's not worth the cost of the tether, which allowed you to remain at a constant height and drag boxes into enemies.
As a side note, I'd like to see missions more like the ones in the original rather than just (kill everything).