Crystal A5 S.E.C.R.E.T

Crystal A5 S.E.C.R.E.T (Secret Enforcer of the Crystalline REactor Tyrant) is the first mission of Project Crystal P5, not counting the bonus two missions. It has 50 rounds, and the mini-boss is the Crystal Bloon, and the boss is the Code Crystal Destroyer. It takes place on the Crystal Mountain. The mission is unlocked by a secret, and has few secret suprises and random secret facts, and also has a secret boss, the Crystal CSX900 Tyrant!

Secret Suprises

 * 1) If a Crystal Submarine is placed near the crystal (yes, it can be placed on both land and water) and is upgraded to 4/2 within 10 rounds of the submarine's placement, AND a missile somehow hits the building, something comes out... the Crystal Tractor's prototype, a huge sniper and the CD Crystalline S, but has a huge improvement. This certainly means that the SNIPER project was getting researched there, and has crystal, the Crystal Tractor and the CD too.
 * 2) If a Crystal Tractor cuts the part of track near the crystal, that part will then release a crystal for 10 seconds, then disappear inside the cave under it. This proves there are still crystals in that cave.

How to unlock the Secret Boss
'' So what's up, Tyrant? I'm your leader, the Colour Bloon. Well, I've planned to defeat monkeys somehow. Just prepare a crystalline tank and a huge nuke cannon that can destroy the whole island from the monkeys' part! Sounds nice, right? So keep stealthy and smart and don't be seen by Crystalline CS. I'm sending a small tank piece.
 * First, defeat Code Crystal. Then, replay the mission, but this time, you must not even reach Round 25 (miniboss round), or else you have to repeat! You must however reach Round 24. Then you'll get a huge Crystalline Tank Piece.
 * Next, read the Bloonopedia's section of Crystal Spirit Bloon. There's a small bloon there, with the letters TYRANT. DO NOT TOUCH. and a letter. It reads:

From: Colour Bloon, your leader.
 * So what's he planning? Sure, there's a small tank piece. Click the piece, and put it in the Inventory. Start the mission again, and reach the last round, then secretly attach the two pieces on the Code Crystal. Then beat it, and destroy the pieces. Replay the mission, and there's the tyrant on Round 50, taking revenge for destroying the tank pieces!