Second Wind is a defensive mechanic that gives you another chance when your tower would otherwise fall. Two labs in the Labs tree build on it: Second Wind Blast adds a clearing effect when it triggers, and Recharge Second Wind lets the effect come back after a set number of waves instead of being spent for the rest of the run.
Labs — Second Wind Blast
Second Wind Blast is unlocked through Milestones at tier 3 wave 150. Once researched, triggering Second Wind also wipes out a percentage of the enemies that have spawned, thinning the wave that overwhelmed you and giving your tower room to recover.
The lab has 4 levels, each raising the share of spawned enemies the blast clears. The exact percentages per level are listed in the data table below.
| Level | Time | Cost | Value |
|---|---|---|---|
| 1 | 1d 3h 47m | 1,800,000 | 25% |
| 2 | 1d 17h 40m | 3,000,000 | 50% |
| 3 | 2d 7h 33m | 4,500,000 | 75% |
| 4 | 3d 11h 20m | 75,000,000 | 100% |
Labs — Recharge Second Wind
Recharge Second Wind is unlocked through Milestones at tier 14 wave 60. Normally Second Wind is a one-time save, but this lab allows it to recharge and become available again a set number of waves after it activates.
The lab has 7 levels, improving how quickly Second Wind comes back online. Check the data table below for the recharge values at each level.
| Level | Time | Cost | Value |
|---|---|---|---|
| 1 | 5d 5h 0m | 550.00B | 2,000 |
| 2 | 6d 14h 21m | 1.05T | 1,500 |
| 3 | 8d 0h 55m | 1.55T | 1,250 |
| 4 | 9d 23h 10m | 2.05T | 1,000 |
| 5 | 14d 1h 59m | 2.56T | 750 |
| 6 | 24d 19h 29m | 3.07T | 550 |
| 7 | 51d 8h 12m | 3.60T | 400 |