Start with the plot that receives the upgrades
Chain upgrades by placing Lab Rat beside plots you can repeatedly level, then finish Concabulator after your important plots are in play. If that chain develops slowly, use Recycler to turn spare cards into adjacent buffs while Mothership or Converter supplies your damage.
Choose the payoff your opening hand can support before filling the kingdom. A promising chain is worth pursuing, but keep enough fighting power on the board to reach its payoff. Treat additional engines as support for that plan rather than reasons to spread every upgrade across unrelated plots.
Choose between upgrade chains, recycling and conversion
| Engine | How to build around it |
|---|---|
| Lab Rat | Lab Rat levels whenever an adjacent plot levels and has no ordinary level cap. Put repeatable upgrade targets beside it so the cards spent improving its neighbours also advance the Rat. |
| Concabulator | Reaching level 3 levels up your entire kingdom. Place your intended recipients before completing it, and keep Lab Rat beside plots whose upgrades can feed its passive. |
| Recycler | Each card thrown into the pit gives adjacent plots +2% damage and HP per Recycler level. Position it to touch Mothership and your intended troop carry, such as Executioner. |
| Converter | Converter turns enemies into allied rats that inherit its stats and gains +1 ray per level. Defenders can hold the fight while it works; Beacons beside it support its attack speed. |
| Mothership | Mothership is a mobile, controllable attacking building. A Recycler beside it turns pit discards into base buffs, while leveling also improves its movement speed. |
Place the receivers before triggering the chain
- Place Lab Rat beside plots you expect to upgrade repeatedly. Build the opening around those neighbours rather than leaving the Rat isolated from your upgrade targets.
- Establish a fighting fallback if the chain is incomplete. For a defensive opening, level Mothership first and deploy Defenders instead of waiting indefinitely for the ideal Concabulator hand.
- Finish Concabulator at level 3 once your important plots are down. Its kingdom-wide upgrade supplies the broad payoff; Lab Rat gains further levels when its adjacent plots level.
- Place Recycler before discarding spare cards. Have it touch Mothership and the troop plots you intend to keep growing, so those throws benefit the actual fighting core.
- Use Overhaul on a disposable plot to level random surviving plots. Keep the kingdom compact when Executioner is your intended recipient, because extra plots spread those random upgrades.
- After playing Overhaul, throw Rewind into the pit if you have it to obtain more Overhauls. Continue only while you have suitable plots to destroy and a fighting core worth upgrading.
Keep the recycling loop supplied
Recycler needs spare cards to keep producing buffs, so card supply matters as much as placement. Earthworks can return up to 3 copies from a target plot, providing cards for further plays or discards. Rewind also refills your hand with copies of recently played cards, and throwing Rewind into the pit itself triggers Recycler.
Keep a card that completes your immediate upgrade chain before throwing away the rest. Judge each discard against what your board needs for the next battle. A hand full of possible future combos is less useful when the current fighting core needs help now.
Match perks and decrees to your active engine
Choose Futurism when ordinary troop levels are limiting your carry: it lets troops level up to 99. Lab Rat already has no ordinary level cap, so Futurism is especially relevant when supporting another troop, such as Executioner. Splicing offers another route to extended level scaling, while Repurpose supports pit synergies.
For a recycling hand, Junkyard adds 9 random Trash cards, supplying material for Recycler triggers. For a Mothership plan, Ultragravity doubles its attack range. For conversion, Proliferation adds +1 Rat per conversion.
Resilient provides +1 starting life when you want more room for a slow setup. Wrathful gives troops +10% starting damage, which suits a troop-led opening. Prefer the benefit that helps your present board survive rather than choosing solely for a combo you still need to draw.
Pivot when upgrades or spare cards stop arriving
If Lab Rat is developing too slowly, pivot toward Defender, Executioner or a supported Mothership. Defenders do not attack; they reflect damage taken, giving you a defensive alternative to waiting for more Rat levels. Steel Coat protects against opening hits, while Reinforce supplies battle healing.
If Overhaul is missing, place Recycler beside Executioner so spare-card discards still improve it. If cards to discard are also scarce, focus on Executioner levels under Futurism rather than expanding the recycling setup. Converter remains a separate option when you can support it with Defenders and adjacent Beacons.
Use the reworked Progress deck
Recycler replaced Precision in the Progress deck, so older Precision-focused openings describe a different setup. Reinforce was also reworked: it grants +2% HP per second during battle and heals beyond maximum HP. Its former Lab Rat interaction should not determine your current upgrade order.