These bosses appear several times. I'm at level 115 and I've seen the Boss Battles about 4-5 times. I just battled Colonel Steele (called "BEAT THE ELITE"). These Boss Battles promise if you beat him 35 times you get some type of Tank. However, unless you spend lots of gold, I don't think you can win more than 14-15 times.
1. The Boss appears sort of at random and seems to alternate between Events where you collect and unpack items for Bonus Units. They seem to appear when you attack something during a Mission.
2. The first few times you see Boss, you can pretty much beat it with just free attempts or a combination of a few pay and a few free attacks
3. At later levels 10-14 you need to basically spend money to beat the Boss. You will get a cash bonus when you win, based on what level you're at (i.e., I got $600,000 at level 14) so that defrays the cost of paying to fight.
4. You get rewarded for each battle you win with a Bonus Unit. The splash screen shows you very enticing units with Attack/Defend scores in the hundreds, however those are "rare" units, that you get less than 10% of the time. In 14 battles, I got one rare unit, five uncommon units and eight common units. Click on the small question mark where it says "And Other Prizes" to see what these units are and what you’re really going to get. I got my Rare Unit on my 3[SUP]rd[/SUP] or 4[SUP]th[/SUP] attempt, so I think the prize distribution is truly random.
5. I think you have 35 attempts, and then the Boss Battle stops running, and then you're probably qued up for the next Event thing to collect boxes. One BAD THING is, when you're still in the Boss Battle, awaiting a new attempt, be VERY CAREFUL with doing a mission. Several times, I won a mission, and just as the thing was dispensing cash, the Boss Battle began and the money sort of disappeared.
Here's some tips:
1. Use the Free Attempt as much as you can and fight the Boss each time to win nice units that are INDESTRUCTABLE.
2. You have two hours to beat him. You will slowly regain health, so you might have to stretch it out, say attack every 20-30 minutes to beat him at higher levels.
3. Pay attention to the event timer. At level 14, I had to wait 30 minutes for my health to recover a bit each time, then with one minute left, I did the final battle, fighting three times, at a cost of $450,000 ($150,000 x 3 attempts) to finally defeat him for the 14th time. After that I decided it was impossible without using gold and simply not worth the cost. To win the 14th battle, it cost me about $1,200,000 about 8 attempts. I did get a $600,000 cash bonus and a lame common unit, so the true cost was about $600,000.
4. If you have just beaten a Boss and are at low health, and want to fight again, do not do a "Mission" or fight anyone. If a Boss battle begins again, you'll start at your current health, which might be 5-10%. Don’t fight or do anything other than collect money for a few hours so you will start at full health for the next fight.
5. You can use Gold for a FORCE ATTACK, pay money, or do the free attack. You can also use Gold to "recover" your health. I've never used Gold, so I'm not sure how well that works. I've been able to defeat the Boss up to 14 times without using gold, and the only way I can see winning 35 times is by using gold for FORCE ATTACKS and recover health. If you're going to use gold, then just buy comparable units outright.
