Nightmare Sphere Guide
This guide is intended to help you with important information to survive. Its not a comprehensive guide to every secret, I do have a life, but it should help you avoid beginner mistakes and give you necessary gameplay information. It also has a god difficulty section.
Controls
This is a game where control of the character is highly important. You have enormous control over the character, particularly as time goes on and you get mobility upgrades, but none of that helps if you have a shitty keyboard setup. Go into the controls and change the default zxc config to wasd. I recommend d for attack, a for jump, s for dash, and w for attack 2. Movement is already bound by default to the arrow keys, which works fine. Your mileage may vary what you prefer.
Stats, in order of recommended allocation
Don't max any stat out, let those random upgrades you find do that.
Str = Makes you hit harder, best stat.
Eva = Stay invincible longer when performing certain moves, very helpful on god difficulty in the long run.
Int = More mp, may affect magic damage, not that useful. Swap with Vit on lower difficulties.
Vit = More hp, useless on god, modestly useful other wise.
Qui = Move faster, this can actually HURT you on high difficulties, you might be hard to control, so don't invest, just pick up items that boost this instead.
Spheres
You use spheres to give your weapons some extra attacks. What I'm about to say is important, so please pay attention. The best upgrades seems to be the up + attack and down (in air) + attack upgrades. These are your bread and butter attacks for the sword and throughout the game. The second up + attack upgrade also gives you essentially a mini jump, which you WILL find useful. I would recommend NOT upgrading beyond these two, because you may not like what it does to your control. Experiment and see what works for you.
Dash vs Roll
The game implements invincibility frames for many actions, like dashing, rolling, sphere attacks, etc. Eva improves these, but the most important thing to note is that there is a BIG difference between rolling and dashing. Dashing gives a BRIEF initial invincibility period, but rolling gives invincibility for the duration of the roll, regardless of Eva. Do NOT get this confused, it will get you killed on high difficulties. You can actually disable ground dashes, or any other mobility upgrade, if it causes problems for you.
Map and fast travel
You can fast travel to any save or 'keep' point by selecting them on the map. Keep is like the mark spell, it creates a return point, and you can create one at any point for free, though only one at a time.
Enemies and stun gauges
Basic enemies in this game are best dealt with through high aggression for the most part. The vast majority of enemies have a small stun gauge, that when depleted allows you to stun them when attacking. The reason Str is the god stat is because the more damage you do, the faster you can stun the enemy and go to town on them, avoiding damage yourself in the process. Note a few enemies can also block or use energy shields. These work like the stun gauge but are typically larger.
Bosses
Bosses on the other hand are more complicated. While they have a stun gauge, it takes either multiple special attacks to drain it rapidly (attack1 plus attack2 at the same time), or gradually wearing it down over the fight, especially when they are charging an attack. Thus you'll spend most of the fight figuring out their patterns and when you can safely attack them.
God difficulty
Any hit by a trap or enemy, with the exception of the "metroid" enemies, will kill you. Needless to say, you will be reloading a lot. Str is critical, learning to rapidly execute the up and down sphere attacks is critical, and for bosses, you MUST be able to use rolling, dashes, and jumping effectively, as well as the patience to wait for a vulnerable moment to attack. I recommend you SKIP the first orc boss (the red on ground one who uses fireballs) you are likely to find first, and instead fight the werewolf. You'll get a very useful air dash that will help in the orc fight.
When exploring, keep/mark often and return to save when making any significant process. This is annoying, but repeating a section is even more so. Just be careful to mark in a location that doesn't spawn an enemy close by. Try to find the items, but don't stress if you can't find the secrets for each area. There are a lot of hidden areas, backtracking, and mobility and spell/upgrade requirements to collect everything, so don't stress about it the first time through.
Magic
The usefulness of magic takes a while to come online, about 2/3rds of the way through. Until you get tri-shot and piercing, magic generally isn't worth using except to clear elemental doors or navigate the the lava and storm areas with ice/earth barrier. Once you get those however, magic becomes very useful, and once you get charge and homing, it's generally better against enemies then your melee weapons, with the notable exception of the armored centaur. Some bosses are also vulnerable to certain elements, so it might be worth it even against them to use it.
Weapons
The sword will be your main weapon for most of the game, as its swift and has a lot of invincibility frames. Its worth noting that the hammer is excellent against bosses however, as its massive damage can even break the stun gauge within a single cycle of boss attacks, usually around the point of the boss charge attack.
Final note
I finally beat the game on God difficulty. My reflexes aren't the best by any means, but it IS doable. I reloaded many, many times, usually it would take between 10-20 tries per boss, though some were definitely easier, (looking at you succubus). I can't say I recommend it to new players, but if you find the game far too easy, then give it a try.
