1. A rainbow rank will give you super automatic fire!

Explanation
Collecting rank markers in order (red-orange-yellow-green-blue-pink) without collecting more than one of each gives you "Super Autofire". You will keep it until you die. This secret is highly recommended

How?
"Hurry Up Ship" can help you out, because they are looting Rank Markers that you don't have. Be sure not to collect ranks from question marks, memory station or shop.

2. Collect the skull of death to increase the chance of added weapons, lives, cash and glory

Explanation
Collecting skulls will increase the chance of GOOD bonuses being dropped by aliens. (Things like QUAD SHOT, EXTRA BULLET, MONEY and X2 CREDITS etc.)

How?
Just collect a skull to complete this secret. The more skulls you collect the hihger the chance.

3. Collect the three coloured skulls to gain triple power of super kind and the best of speed!

Explanation
Collect 1 skull of each color (Skull Red, Skull Green, Skull Blue) in any order and you will get SUPER TRIPLE SHOT as well as extra speed, bullets and time!

How?
Just collect 1 skull icon of each colour to complete this secret. The secret even counts if you own a better or the same weapon.

4. To see the color of the missing skull go to the Meteorstorm!

Explanation
When collecting one skull of each colour, the shading of the meteors in the Meteorstorm bonus level will let you know which colour you haven't already collected.

How?
Just collect a skull icon and go into a Meteorstorm to complete this secret.

5. Three skulls of red will make the counting of the gems visible to see!

Explanation
Known as *** GEM COUNTER ACTIVATED ***.

Collect three Red Skulls and the GEM COUNTER will be activated. This will show you how many gems you have collected in the correct game. Collecting 100 will bring you to the GEM DROP level (see secret 6).

How?
Just collect three Skull Red to complete this secret.

6. Collecting many small gems may bring you to the collecting of the big and valuable ones!

Explanation
Collect 100 gems and you will go to the GEM DROP level where you can collect many large gems for big points!

How?
Just collecting gems from a several Gem Bombs is usually the best way to complete this secret. You also get gems in METEORSTORM level (5 gems for eaach collected big gem) as well as from MEMORY STATION.

7. When many gems are falling from above pull them to yourself by pressing down!

Explanation
Pulling down will draw any falling gems towards you.

How?
Collect a gem bomb and press your "down" button.

8. Three skulls of blue will make the money from the thief look like the skulls!

Explanation
Known as *** BLUE COIN MODE ACTIVATED ***

Collect three BLUE skulls. After you manage to kill the "Big Trouble" bosses or the Money Thief ship they will drop all BLUE coins (which are worth 200 credits each) instead of dropping random coins. This secret does not work for the Moneyship.

How?
Just collect three Skull Blue to complete this secret.

9. Three skulls of green will make doubler appear at start of falling rocks!

Explanation
Knows as *** MS MULTIPLIER ENABLED ***

Collect three GREEN skulls and a point multiplier (x2 or x5) will appear before each Meteorstorm.

How?
Just collect three Skull Green to complete this secret.

10. At the end of meteor trouble having a multiply will bring you great points!

Explanation
Completing a Meteorstorm with a multiplier (eg. Like the one unlocked by SECRET above) will multiply the extra bonus points you receive at the end!

How?
Just make sure you have got an x2 or x5 multiplier going when you reach the end of a Meteorstorm to complete this secret.

Source: warblade.fandom.com