This is a complete guide for unlocking all achievements in the game. Naturally, this guide itself is a huge spoiler, so only read further if you are aware of that.

None of the achievements are missable. There is one difficulty-related achievement for beating the game on Hard Mode and another achievement that can only be completed in a second playthrough, which can also be counted as difficulty-related. Thankfully, the game has a short playtime, so challenging yourself with these achievements won't take too long and offers a new experience. The in-game save game time stood at roughly 4,5h after beating the game on Hard Mode, including beating all bosses and collecting all items.

This guide is subdivided into three sections: Mandatory story progression achievements, optional completion achievements, and optional difficulty-related achievements.

This section lists all mandatory story progression achievements in sequence, which can't be missed while beating the game.

Step foot into the Sunlight Zone

Step foot into the Twilight Zone

Step foot into the Midnight Zone

Step foot into the Abyss Zone

Step foot into the Core Zone

Beat the game

This section lists all optional completion achievements. They are not missable. After beating the game, you can still access the most recent save to complete the remaining stuff.

If you struggle to find anything, in the Twilight Zone behind a laser that is deactivated by destroying 5 crystals in this area, you find the Discharge Detector that automatically marks items on the map in a white frame.

Defeat all bosses in the first four zones

Beat the game after collecting all items

This section lists all optional difficulty-related achievements, where you must beat the game from start to finish on the respective setting. The difficulty can not be adjusted during a playthrough.

Here, are three tips for you that can make the game easier.

First, activate the option to display the HP bar of enemies at all times. They blend less into the environment and you always have a better estimate of how close you are to killing them.

Second, the game will automatically save any collection progress. Quitting and reloading puts you back to the last save point you manually saved. This can get you out of tougher situations faster.

Third, here is one technology that will make this significantly easier: Shield Nullifier. One shield is usually 10 HP. This item converts every shield into 1 HP but every hit will only give 1 HP damage. Given that later enemies deal >10 HP per hit this technology is basically one massive health upgrade. But at the same time, the Reverberating Armor will now be a useless technology.

Beat the game on Hard Mode

I recommend starting your first playthrough on Hard Mode for two reasons. First, you don't need a separate playthrough. Second, the next and last achievement introduces many modifiers that make the game more difficult but it unlocks even on Easy Mode. If you are already accommodated to Hard Mode, turning it off will counter the perceived added difficulty a little.

Hard Mode applies these three challenges to your run:

• You take more damage
  
• Bosses have 1.5x health
  
• Saving will only heal up to 10 energy

Beat the game with all modifiers on

This one can not be done as your first playthrough because you need to get all 9 other achievements to unlock all modifiers. This achievement can be unlocked on Easy Mode.

The 9 modifiers are:

• Xanthiom of Sunlight: All enemies have 25% less health. You take double damage from enemy attacks.
  
• Xanthiom of Twilight: Deal 1% less damage for each 1% of total items found. Minimum 20% damage.
  
• Xanthiom of Midnight: Taking damage poisons you. Poison is removed after healing.
  
• Xanthiom of Abyss: The world is dark.
  
• Xanthiom of Core: Enemies do not drop energy orbs.
  
• Xanthiom of Mind: Skip cutscenes and most dialogue.
  
• Xanthiom of Soul: Begin the game with 4 shields. Shield upgrades do not increase your maximum health.
  
• Xanthiom of Body: You have every technology equipped.
  
• Xanthiom Zero: All items are replaced with crates, which grant random items.

Most of these modifiers sound really bad but for me, the challenge was easier than Hard Mode for the most part. However, I admit that I got lucky with a few pickups early and I also used this website's map[demajen.co.uk] for the game to navigate the game quicker. It took me approximately 1,5h to get this achievement. Now I'll explain how the modifiers impact your run and interact with each other:

First, the Xanthiom of Body is the most important to keep in mind. You will have the benefits of all technologies at the same time, all the time. No need to choose, a massive boost for your stats from the get-go. Here, I assume you are familiar with the Shield Nullifier technology, which I explained above. The Xanthiom of Sunlight, however, makes every enemy hit two times harder. Each hit by an enemy distracts 2 HP, even with the Shield Nullifier active. Every non-enemy hit remains at 1 HP damage. At least, there are three technologies that, together, provide 3 more HP. But with the Xanthiom of Soul active, you will be at 8 HP for the whole game (1 HP base health + 4 HP by shields + 3 HP from technologies).

The start of the game will be the hardest because the Xanthiom of Midnight will basically put your remaining health after receiving damage on a countdown that periodically distracts 1 HP until you die. It synergizes with the Xanthiom of Core because this will prevent spontaneous healing instances and nullifies partly the Energy Charger technology. You are limited to save points, warp points, and energy points as healing sources at the start. Getting the Up Dash upgrade is crucial since it allows for a reliable healing source via the Reverberating Armor technology to stop the poison effect. Heals restore 2 HP through the Energy Charger technology. Using an elevator to travel to another zone also stops the poison effect, although it does not heal you. Before it, staying at maximum HP is also very important to profit from the damage-boosting Energy Disperser and Power Siphonator technologies.

The Xanthiom Zero combined with the Xanthiom of Twilight also poses a big threat. You can not crawl the map for the most broken combos and all the damage modifiers. I don't know yet how the Xanthiom Zero influences mandatory progression items (but probably there will be no soft-locking seeds). It's possible to skip parts of the game if you get lucky and find progression-relevant upgrades early. The now obsolete Tech Points and the now obsolete Shield Upgrades can still appear in crates. The crates' contents are not fixed at the start of the run.I verified it by opening a crate, reloading an old save game, opening it again, and not getting the same item. Of course, this allows for save-game-scumming, should this challenge be not up your alley. The crystals you have to destroy in the Twilight Zone are still at their usual locations. The same goes for the three pearls in the Midnight Zone, the three keys to access the Core Zone, and boss encounters.

I don't know the game's damage calculation logic. Many games apply modificators additively on the base damage, instead of multiplicatively. But I try to discuss it a little bit here, and any additional insights on this matter are very welcome. If it's strictly additive, the 7 damage modifiers give you 70 percent points onto your 100 percent points base damage, and the Xanthiom of Sunlight distracts 100 percent points and leaves you with 70% of base damage. If it's multiplicative, it would be 1 times ~1,95 (1,1 to the power of 7) times 0,2 equals ~39% of base damage. But without knowing the code, or analyzing the inflicted damage more thoroughly, I can't tell, and there could even be combinations that yield different results. I hope, the 25% health decrease in all enemies (I don't know whether this includes bosses) from the Xanthiom of Sunlight actually reduces their health, because then, mathematically, we could multiply the prior results with 1,33 resulting in either 93,1% or ~52% of base damage.

The rest of the technologies mostly just shorten cooldowns but don't interact much with the prior technologies and modifiers. Mainly, they put more emphasis on dodging via the Zip Dash, and using your missiles more often offensively, both because they are more viable now but also because the modifiers force you to leverage any advantage possible.

For the remaining modifiers: The Xanthiom of Mind can safely be ignored. And the Xanthiom of Abyss just makes most of the screen go dark. Only your imminent surroundings and the vicinity of each enemy are lit up. For non-platforming sections, you could argue this is actually good since enemies are more easily trackable. These two modifiers, fortunately, don't create any disadvantageous synergies.