- goal for each level represented by progress meters
    - kill the boss
    - kill n eggs before they hatch
    - defend stationary vip for x turns
    - reach a location within x turns
    - collect x well-guarded items
- you only get an upgrade if you complete the goal
- on the final level the goal is to escape
- persistent progress bar of how many metres are left
- meters
    - active
        - gun: charge by collecting ammo.
        - medkit: Charges over time. Use to drain and heal by square of current charge.
        - personal teleport: Charges over time, fluctuating between full and empty.
                Use to teleport by distance determined by current charge, draining charge into negative.
        - kinetic pulse: When fully charged, discharge to knock back nearby enemies
    - passive
        - health: charge by using medkit or collecting bandages. You die when it runs out.
        - kevlar: charge by collecting scrap. Probabilistically absorbs damage when non-empty, draining by 1.
        - gasmask: charges over time. Drains when in gas instead of health.
        - compass: shows the distance to your nearest goal

