Complete the indicated task in the listed level to unlock the corresponding hidden Boss.
| Boss | How to unlock
|
|---|
| - Get 25 Coup de grace attacks before 80 kills.
|
- Gnezdo (High Sea Fortress)
| - Get 40 melee kills before 80 kills.
|
| - Get 15 Counter Kills before 80 kills.
|
- Strelat (Mining the Depths)
| - Kill 70 enemies before 600 seconds.
|
| |
| - Get 25 Quick shot kills before 80 kills.
|
