Tip: explain rockets, add more guns. Looks pretty decent, I like the circle. Maybe make it also act as a partial barrier? pretty good, you will likely get better.Also, try to update and not spam 100 games.
I found the loot okay - I focused on saving up when I could then buying a weapon that would last, and help me through many levels without grinding. That way I could wait a long time before upgrading armor, as that requires you to make 6 targets close to equally armored. You can use autofight to grind earlier levels - the 3rd city was very good grinding, as I won battles with autofight 99% of the time and loot was OK.
Instead of having shield + skills, there should be shields on you at once max skills, and you start with max. Then there should be damage and/or multishot skills, and make it so you can choose skills!
Tip: Making a shaft straight down saves energy. I made mine near the savepoint so if I can't kill myself after a long dig by using up my last bit of energy on accident.
1. The beach is so far away, i got confused and thought it was underground. Please, could you indicate that it is VERY far and aboveground? 2. At many times it is cheaper to buy a new chassis or battery than buy a refill -.-