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Super Mario 3D All-Stars

Galaxy Overview

Ben Chard
Jarrod Garripoli
, &
Seren Morgan-Roberts


This page offers an overview of Bowser’s Star Reactor. Bowser’s Star Reactor is located in the Fountain dome and costs 15 stars to unlock. This is the boss galaxy of the Fountain dome, so you will receive a Grand Star for completing The Fiery Stronghold.

The Fiery Stronghold

This level has 4 areas. Your aim in this level is to defeat Bowser to grab the Grand Star!


  • Fire Bars - Fire Bars will rotate and are often an obstacle that you will have to jump over (or you can wait for them to pass). They inflict fire damage, which makes Mario jump around erratically - they’re especially dangerous when you’re on a narrow path!

  • Thwomps - Thwomps will crush Mario and defeat him instantly if he is standing beneath them when they crash down. You cannot defeat them in this level, so you’ll just have to avoid being crushed by them.

The Thwomp will crush you if you linger too long beneath it.

Boss Enemy - Bowser

Once you’ve reached Bowser on the tower, you’ll be transported to a small planet with a handful of blue domes on it. Bowser attacks in a few ways:

  • Fire Balls - He will spit out a few fireballs and they will bounce around for a bit before disappearing. They are easy to avoid but will inflict fire damage if they hit you.

  • Electric waves - When he jumps, Bowser will create circular electrical waves that go around the entire planet. To avoid them, you’ll need to jump over them. Sometimes he will create up to 3 consecutive rings that you’ll need to jump over one after the other to avoid.

  • Groundpound - When close to you, Bowser will attempt to groundpound you. You can easily get out of the way of these attacks. You will also need to utilise these groundpounds to take him down during this boss fight.

(1 of 2) In this image, Bowser is spitting out fire balls

In this image, Bowser is spitting out fire balls (left), and in this second image, you can see Bowser performing a groundpound as well as electrical waves. (right)

Bowser will mix and match which of these attacks he will perform. You will want to get him to groundpound specifically on the blue domes though. So run up to him and guide him towards one of the many blue domes and then get him to groundpound it. Make sure you’re not standing on it though as it will smash and expose fiery lava.

This lava will damage Bowser causing him to run away from Mario. You will need to run around the planet in the opposite direction to catch him, as you won’t be able to chase him in the same direction he is running - he’s too fast! When you catch him, spin attack quickly to incapacitate him. This will cause him to spin around the island in his shell. Do the same thing as before and run the opposite direction to where he is headed so you catch him on his path. Spin him again to damage him. If you don’t catch him in time during either of these phases, you will have to repeat the process again.

Spin-attack Bowser whilst he’s fire damaged.

You’ll need to perform this series of actions two more times, for a total of three lots of damage. Each time, he will become more aggressive in his attacks by spitting out more fire balls, creating more electric waves and groundpounding faster. He will also run away and spin in his shell faster, making it trickier to catch him. On the third and final phase of the fight, you will need to spin attack his spinning shell form twice in order to finish the boss fight.

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Guide Information
  • Publisher
  • Platforms,
  • Genre
    Action Adventure, Platformer
  • Guide Release
    24 September 2020
  • Last Updated
    8 February 2021
    Version History
  • Guide Author
    Seren Morgan-Roberts, Jarrod Garripoli, Ben Chard

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This guide for Super Mario 3D All-Stars offers a walkthrough for all three Mario classics.

Inside this guide you will find:

A 100% Walkthrough - For Super Mario 64, Super Mario Sunshine and Super Mario Galaxy.

A complete guide on Super Mario 64, including:

  • A layout of Peach’s Castle, with each course’s location pinpointed, as well as an overview of each course.
  • Walkthroughs for every star, including all courses’ 100-coin star.
  • How to get each of the power-up caps.
  • The location of every single Secret Star found in Peach’s Castle.

A complete guide on Super Mario Galaxy, including:

  • A Dome Overviews page outlining every galaxy found in each Dome.
  • Walkthroughs for every star, including hidden stars and comet stars, found in each galaxy.
  • A guide on how to unlock the Planet of the Trials galaxies.
  • Detailed coin-by-coin walkthroughs of Purple Coin levels.

A complete guide on Super Mario Sunshine, including:

  • Walkthroughs for every shine in every episode.
  • How to find every Blue Coin.
  • Strategies on how to secure 100 Coins on every Course.

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