Great game. 5 of 5 for up to insane. Higher difficulties are as the name suggests, impossible. Even with 90% of investment in health(over 500k), surviving the hot drop into a level is instant death. With only one ok set having defense and no good defensive stats to look for, the loot stops making a difference. Flat health regen might be something to change to %.
Something that really helped me was a barricade/miner combo. Later the physics lab makes this very good. For many of the missions you don't need defenses or generators, just minors/ physics labs. It works because the miners are making money while boosting your numbers. Choose whatever ships you want to accompany and it worked all the way though the game.