I've been the game on very easy consistently and I'm working on easy, but it's definitely harder to ration resources (usually end up with ~500 of each when beating too easy).

I remember there was a reddit comment where someone posted on pretty much how to use each character and what levels to take them to. What to focus on with each floor... I can't find it though. Anyone know where it is?

Here are some of my own favorite tips to beat it at very easy:

1) Early on just try to farm resources and pump everything into research. Level characters to level ~4 when appropriate so you can get operators.

2) Floor 5-10 continue what you were doing before but don't be shy on using modules for defense. Pepper spray in one room followed by an AOE room (slow module x2 tear module x2) will clear out almost everything. Research the shop and the power generator. Get level one mechanical pal for those 2 modules.

3) Top floors: Build a power generator almost asap assuming you've stockpiled resources successfully (300 ). By now many modules should be level 4. Build a shop if you find a vendor early. At this point you need to farm your dust because the game won't be giving you anymore unless you're very lucky.

4) Get the aftershave for your door opener, this way they can kill crystal golems and gate-rhinos.

5) Level your runner or major defense character, operators can be left at a certain level since they just sit at a room to generate resources.

I got all these tips above from the post I was looking for, but I'd love to go back and read up on it again :S