There appears to be a FREAKING HUGE advantage with the Revenant's launcher when playing with the mouse instead of the keys. Here's a little experiment:
1) Aiming RevL with the keys gives you an 8 tile range:
2) Then with the mouse, say a 32 tile range:
3) Does it work? Hell yeah!
4) It goes all the way to the other side of the level...
5) ... 'cept the missile seems to get distracted en route. It doesn't actually arrive there...
...and judging by the last picture, it doesn't actually end up anywhere either; nothing else seems damaged in the missile's path (I tried this in another level as well, where I pressed prtscr instead of F10, had the same results).
Being able to hit something at 32 tiles (and possibly more) with pin-point accuracy is just.... wrong. Additionally, so is missiles going AWOL after being fired. With a weapon like this, a hard-coded max range might be in order, which would of course have to be the same for those who have the advantage of a mouse.