Well, except those glitched trophies, this one will probably cause the most trouble for trophy hunters.
You will have access to the expeditions mode from the title screen. The basic rules of the score attack is to do all kinds of score-winning actions including gathering blue orbs, ammunition, resources, documentations, etc.. Killing enemies and shooting lanterns gives much higher score. Every time you score you will see a combo meter at the upper-left corner of your screen. The meter drops down really fast and re-fills when you score again. If you can keep a really high combo, your scoring actions will have a pretty good multiplier and your final score will benefit from it tremendously. So having a good route in each level to keep your combo multiplier is the key.
Also the cards you select before the level can give you a very good multiplier at the end. Those cards give you some negative effects which are not that scary at all. For example, “one life” card means once you die, you have to start over while it gives you 100% more points at the end. This actually means nothing considering most levels are extremely short and some of them do not even have any enemies. If you do not have many good cards, just go to the leader board and find your level, select anyone at the top of that board, you will have an option to challenge his score with his card set for 2000 credits. This counts towards to trophy too. What is even better is that if you fail in the middle of your run, you can just “restart” the level without having to pay another 2000 credits.
I found this video list really helpful, especially for showing a good route. Credit to dormouse03.
Some other tricks I found myself during my run:
1. The most important thing first: unlimited poison arrows card. This card will give you 50% less points, but man, it helps so much in those enemy encounters. You can use poison arrows to shoot lanterns too. If you do not have this card yet, no worries, go to the leader board, and you will find it from the card-set of those top ranked people.
2. During the level where you need to shoot some gates with fire bombs (I think it is called outskirts of the lost city?), you will come to a point where you are supposed to shoot 3 groups of undead enemies with that big machine. Instead of doing that, you can use your unlimited poison arrows to shoot them. They will always respawn which gives you theoretically unlimited points.
Hope this solution can help you in any way.