What the official description confirms
The current itch.io description says that each building increases the cost of all future buildings. It also says players need to purge factories from time to time. Those statements establish the pressure behind the economy loop, but they do not publish a best factory mix or a fixed income-to-price trigger.
Track the cost curve before it tracks you
Use the same checkpoints in every attempt. The aim is to see whether a purchase adds enough frontline output before the next price increase, not to chase a magic number.
| Checkpoint | Record | Question for the run |
|---|---|---|
| After a new factory | Price of the next purchase | Did the new line change the wave outcome or only add idle capacity? |
| Before a larger expansion | Current income and battlefield pressure | Will one more factory solve the present problem, or merely raise later costs? |
| Before a purge | Factories, upgrades, war points, and next rebuild goal | What persistent advantage will make the rebuild faster than the current inflated run? |
Interest and coin choices need a stage check
A developer comment described interest as a small contributor around Level 20 and as capable of reaching roughly +3k later in that discussion. That is useful context, not a universal per-cycle value. Community comments also report that an early coin route can be disrupted by level skips.
- Compare an interest or coin purchase with the immediate combat problem it delays.
- Write down whether a level skip changes the time you actually benefit from the upgrade.
- Re-test after patches; neither comment establishes a permanent priority route.
A safer purge checklist
- Confirm that the next factory price is the actual bottleneck, rather than a missing combat or economy upgrade.
- Note what you will rebuild first and what wave or level you are trying to reach after the reset.
- Spend only resources you are comfortable committing; keep the run’s before-and-after numbers.
- After purging, compare the rebuild pace with the old run. If the test is inconclusive, repeat under the same conditions.
Persistence boundary: the official death description says upgrades and war points persist while factories are lost when death sends the run back. It does not, by itself, prove that purge has identical persistence rules, so this guide keeps those events separate.
Related guides
Use the upgrade overview when a purchase is competing with a branch choice, and the progression overview when a death or level skip changes your test conditions. The unit comparison page will collect matchup evidence once version-matched runs are available.