- Completing Korma level 20 unlocks: Super New Ship Type 1, and Madras levels 1-30.
- Completing Madras level 11 unlocks: C64, and Korma levels 21-30.
- Completing Vindaloo level 11 unlocks levels 31-40 on Korma and Madras.
- Completing Vindaloo level 40 unlocks Super New Ship Type 3, and all Phaal levels.
- Completing Phaal level 11 unlocks levels 41-50 on all lower difficulties.
- Completing Phaal level 50 unlocks Super New Ship Type 4.
The semi-official summary: To unlock things, play more.