Got my first new PS4 game plat - Resogun!
Here are two tips for anyone trying the 15x multiplier trophy: I think its better to play on Veteran and to play on the 3rd level.
I did the first level and kept the multiplier all the way to the end, beat the boss and lost it right at the beginning on level two because it's only around 13x by that point and there aren't many enemies at the beginning.
So instead I found level 3 is much better for this, which after reaching the boss you can pick up the remaining multiplier points by shooting the small cubes he sends at you.
Also for saving all humans you may notice some die right away without keepers coming out. These humans require that you have a specific multiplier such as 3x or 4x at that time. That was the last thing I was misunderstanding. A trophy guide should tell you what human # that requirement is on.
