Double Kick Heroes

This guide will help you kill Rex (chapter 2 boss battle) on your own in the most efficient way possible. This is very doable solo, but if you are still having trouble, you can have a second person help you via Xbox's copilot feature. Have the more skilled person take the most important double kick lane, and the second less skilled person take the snare and cymbal lanes.

This achievement stacks with the following:





Here's the tutorial video, along with the full description from YouTube posted below. Check out the last paragraph for boss specific strategies.


This is a tutorial on the most efficient method to kill Rex on Extreme difficulty, on the Xbox One. You can obtain the achievement on either Story or Arcade mode. I played on Arcade mode so I could show off the full chart.

First of all, make sure you spend time tweaking the settings. Go into Gameplay and turn on the "No Overheat Mod", and change "Musical Score Speed" to x0.5. The "No Overheat Mod" allows you to spam as much as you want with no penalty outside of losing your streak. Changing the "Musical Score Speed" gives you more time to see the notes, but more importantly, it increases the size of the timing window, making it MUCH easier to keep your streak going. You can still earn any achievement in the game with these mods on.
Next go into Controls and make a custom control scheme. Both default options are terrible in my opinion. Make sure that the up kick and down kick are mapped to separate thumbs, then use the bumpers and triggers for snares and cymbals. I personally chose right on the d-pad for down kick and X for up kick, and then LB and RB for snares and LT and RT for cymbals.
Finally, go into Sound and tweak the Audio/Video Calibration. The Video Calibration test works fairly well. The calibration changes every time you hit RB, so keep hitting RB with the flash until it stays pretty consistent. For me, I landed at -25 MS. The Audio Calibration test is completely broken unfortunately. Thankfully, the game is very good at indicating if you are early/late during gameplay. If you notice that you are consistently late in a song, then increase the audio delay (ex: move it from -50 MS to -70MS), and vice versa if you are consistently early. For me, -220 MS is where I landed eventually (that seems like a crazy high number but it worked for me for some reason).

Now for general boss fighting strategies:

Always focus on the double kick lane first. This is the most important lane by far, because it does the most damage, and anytime you miss a note or hit the button too many times, you lose your streak and go back to the pistol, which causes you to miss out on a lot of damage potential. However, the snare and cymbals don't affect your streak at all. You can spam them, or ignore them, and still maintain your double kick streak. The more you hit the snare and sniper, the more often you will throw grenades and fire sniper shots, so they can be useful if you can manage to hit them. But you never want to hit them if it causes you to lose your double kick streak. The sniper is more important than grenades in boss battles, as it does single targeted spike damage; so focus on that before grenades, if you have to.
A very nice thing about this game is the HUGE timing window. You'll notice that there are 'Perfect', 'Good', and 'OK' timings. These all have different point totals, but they all do the exact same amount of damage against the boss. Which means if you hit the notes anywhere in the massive yellow timing window, you do full damage. You can completely ignore the timing of the songs and just hit the notes whenever they are in the square and still do fine. Use this to your advantage on the fast parts! Instead of alternating back and forth, it might be easier for you to hit both up and down kick at the same time.

Now for this particular boss fight:

Rex can be killed by focusing only on the double kick lane, but with little margin for error. You may have to throw in some sniper shots if you lose your streak even once. There are a couple of odd graphical glitches (1:23, 2:43) in this fight; try not to let them throw you off. This is the easiest and slowest boss song chart in the game, so getting a full combo shouldn't be too bad. You might get hit once or twice by velociraptors, but as long as you don't get hit three times and get a game over, you won't miss out on any damage. If you keep the streak going, you definitely won't get a game over.

Rex is the boss of the chapter 2.
To unlock this achievement, you'll have to beat it on EXTREME difficulty (and you'll also unlock achievements for VIOLENCE, METAL and Hard Rock difficulty).

First, you don't have to beat the boss in Story mode, you can do it in Arcade (you'll have to unlock the level before by progressing through campaign, though)

Second, you have to kill the boss and not simply survive through the level. So, there is a hidden countdown before the boss run away. You'll have to do a great performance to beat him.

Third, I advise you to change the gameplay type in the options, and to chose the buttons you prefer to use.
Personally, I chose and respectively for "shooting up" and "shooting down", then and for the grenades, and finally and for the sniper.

Finally, if you have trouble with bosses (and you should have, especially in high difficulties), here is a great tip to help you, if you have another player (and another controller) with you.
Use the Copilot feature of the console :
- Turn on both of the controllers.
- Go to the console settings.
- Select "Ease of access" (the last category), then "controller".
- Select "Copilot settings" (that should start the app).
- On the bottom, select "Activate Copilot".
- Now, the two controllers are used for one profile.
- Once in the game, have a player focused on the first two lines, the other one on the last line.
With that tip, it will be really easier to defeat the boss.


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Another great tip shared by Enluna :

These boss achievements are nuts. As in the previous guide, I do recommend using two people with copilot mode if possible. I recommend doing the whole game on easy and the tackling these later.

Check out the video of me beating it on extreme for reference.