Will list all areas in the game here and how to get to them since many of them are optional.

Guard Sword
Initial sword, no way to miss.

Wrong Sword
Buy for 100 gold in Alexandria.



Mirror's Edge
Castle Dungeon, just follow the path.



Boomerang
Found in Cave of Serpents, down and left from Red Spider screen.



Executioner
Drops from enemies that use axes, best screen to get this if you want it early:



Which you get to by following the main path in Castle Entrance, you can't miss it.



Runic Blade
Frog gives it to you after fight in Grand Hall.



Moon Bow
Found in Grand Hall up from the chest that Frog opens, do not enter the door that appears and continue up through a bridge, the chest is against the right wall.



Sword of Dawn
Found in Castle Dungeon after you have Wing Boots, jump right of the chest that had Mirror's Edge and continue, you'll have to defeat a boss and get Jail Key so the door where the chest is opens.



Darkness
Found in Torture Chambers (left of red demon head). As you go along the main path you'll see a breakable wall:



After completing the jump puzzle you get the sword.



Bro Sword
After fight with knight with sword and shield in Windy Ruins, it's part of the main game path can't miss it.



Gungnir
Bought from the Jail in Grand Hall, you need the Jail Key from Castle Dungeon and 13000 gold to boot.



Castael
Reward from fighting the infamous crab boss, you find him in Sorceror's Quarters by going up all the way from the 1st save point, you'll need the Summon Falcon magic.

Guard Armor
Initial equipment, no way to miss it.

Chain Mail
Found at the top of the Clock Tower, you need the Clock Tower Key. When you leave you get attacked by Razor Wing.



Plate Mail
Bought in Castle Grounds for 1500 gold, you can't miss the man since it's on the main game path.



Green Tunic
Found in Grand Hall on a side path, you need to complete a tough platforming section unless you have Wing Boots. It's found between the 1st and 2nd save points.



Heavy Armor
Found in Windy Ruins right before the sword/shield knight boss, it's a door with a platforming section inside.



Blood Armor
Found in House of Ruth. From the save point before the Ruth boss fight go left and on the lower path until you reach it.



Dark Armor
Inside the Cabin found in Agros Forest. You'll need the Cabin Key from Torture Chambers and the Executioner to open the floor in the Cabin.
Hint: The ghosts can be killed with T. Blast from Torture Chambers.



Dream Mail
After buying the Dreamstone from House of Ruth go sleep at the Inn in Alexandria.

Fireball
Given by Marcel the mage, can't miss it.



Energy Splash
Found in House of Ruth, from the 1st save point go right and on the lower path and you'll find it, it's opposite of the coded door.



Storm Shield
Found in Cave of the Great White Ape after beating the boss.



Soul Blazer
Found in Cave of Serpents. Continue right from where the Boomerang was (down and left from Red Spider), you'll need Mermaid Statue.



Summon Falcon
Up from the save point in Alexandria that has the Inn sign.



Gale Wind / Gale Cutter
Up from the chest that Frog opens in Grand Hall, it's in the door you find. You'll have to defeat Razor Wing again and then trek back the way you came and it will be in plain sight. You can only get Razor Wing to appear if you defeated him at the Clock Tower in Alexandria.



Crystal Shock
Found in Alexandria early on, you need Wing Boots though. It's up and left from the Skeleton boss and the guy that gives you Clock Tower Key.



Explosion Fire
Found in House of Ruth. You need Ruth's Key and on the path to Ruth you'll see a painting with a hand pointing down, the spikes there are fake. Also left of the 2nd save point.



To leave you get caught by the hand.



X-Sword
Reward for beating the Crystal Tower. You need Vortex Prism to get to Crystal Tower and then you have to defeat 3 bosses. Crystal Shock, Gale Wind and good HP is recommended.



Thunderblast
Dropped by red demon head in Torture Chambers by deflecting his own attacks back at him.

Clock Tower Key
Found in Alexandria inside the building after the Mr. Arrey boss fight. Talk to the man and he'll throw the key at you when you're preparing to leave.



Sushi
Dropped by Mermen in Sunken Temple, this is the place to farm for it:



Be careful to wait for the puffs of smoke to go away before leaving the screen since the chest might not drop instantly.



Chicken Dinner
Found in Castle Entrance on the main path, there's a breakable wall where the Chicken is.



Jail Key
Found in Castle Dungeon. Need Wing Boots to jump over the Mirror's Edge chest, you'll have to fight a boss to get this item.



Willow Nut
Found in Agros Forest after getting Wing Boots. There's a branch you can jump onto early in the forest coming from Alexandria, it's on the main path.



Cabin Key
Found in Torture Chambers. Reward for completing the Torture Chambers, you'll need Wing Boots and Summon Falcon to complete it.



Museum Key
Found in a chest up from the 1st save point in Sunken Temple, you'll need Wing Boots and Mermaid Statue. [It appears the jump will be made easier in 1.04]



Ruth's Key
Found in House of Ruth. You need Wing Boots and then from the 1st save point you go on the upper path and left when it splits until you find the ghost boss which you need to defeat to get to the chest with the key. This key allows you to get to Ruth and enter the Matt's Key 1 room.



Vortex Prism
Found on a secret path up from the 1st screen of Windy Ruins just left of the warp of that area.



After completing a somewhat challenging platforming section you'll get to the chest.



Book of the Dead
Given to you by a mysterious cloaked figure in Castle Grounds. Can't miss it.



Lost Page 1
Found above one of the save points in Castle Entrance, it's the save point that's near the entrance to Torture Chambers.



Lost Page 2
Found in Grand Hall. There's a vertical screen with multiple vines and metroid lookalikes, on the right wall is a secret entrance to this room. Need Wing Boots to get up there



Lost Page 3
Found in Castle Dungeon. After defeating the boss and getting the Jail Key one of the 5 jail doors will lead to this page, you need the Wing Boots and skill at bouncing from breakable blocks.



Lost Page 4
Found in Castle Entrance. On the same room where you find Chicken Dinner there's a breakable wall on the left. You'll need Wing Boots and Spiked Cleets to be able to jump on the enemy and double jump up to the page.



Lost Page 5
Found in Torture Chambers. Torture Chambers is optional but you can't miss this page if you're already there.



Lost Page 6
Found in Torture Chambers. On the later parts of this area there will be a upper path with spikes and a lower path with 2 saw blades, you get this page on that path. This is one of the difficult pages to get.



Lost Page 7
Found in Grand Hall. After getting the Wing Boots if you backtrack a bit you'll find a path up that you couldn't access before, the page is there. This screen is near the Jail where you buy Gungnir.



Lost Page 8
Found in Windy Ruins on a secret area. Drop down from where the eye boss is and you'll land on a ledge with breakable blocks, there's a hidden door inside that area.



Which after a tough platforming challenge will net you another page.



Lost Page 9
Found in Windy Ruins. There is a Blue Lion in this area that has spikes underneath, those spikes are all fake and lead you to the page.



Lost Page 10
Found in Sorceror's Quarters. In the 1st screen of the last area you find a breakable floor, you need the Executioner to break the floor and get this page. The area that has the page is dark so Torch is heavily recommended as the platforming on this section is the worst of any page. If you're not confident you should save at the Windy Ruins save point instead.

Ares Gauntlet
Found in the Museum inside a door on the lower portion of the area.
Allows you to break blocks that appear cracked.



Mermaid Statue
Found in Castle Entrance. Need Wing Boots or as of v1.03 a good damage boost on the eyeball enemy. From the 1st save point go to the screen where you activate a bunch of blocks, with the boomerang you can activate the one inside a wall which will take you to a boss. After the boss you find this in a chest.



Warp Stone
Found in Castle Entrance. This is in the chest you get at the end of the area after defeating the Golem boss.



Wing Boots
You can't miss these. You find them before the 2nd Frog fight in Grand Hall.



Torch
Found in Windy Ruins. You'll see a chest on the main path through the area but you'll have to drop from above onto it to get it. This is before the 1st boss fight of the area.



Midas Ring
Found in the 1st house of the game in Alexandria but need Wing Boots.



Dreamstone
Bought in House of Ruth for 20000 gold. You find the salesman behind the wall where Energy Splash is, the wall there is fake. You can check the gold farming section if you're short on gold.



Spiked Cleets
You need to talk to Sofiya's father in Alexandria to trigger her appearance, her house is very near the end of the city, it's above and to the right of the save point that has a different background from the rest of the screen, a bit before the General boss fight.

You need to save Sofiya in Agros Forest and then visit her house in Alexandria. Sofiya is after House of Ruth's entrance:



After rescuing Sofiya you can walk back to Alexandria to get a reward:



White Orb
This is the reward for completing the Sunken Temple, an optional area that requires you to have the Mermaid Statue and the Wing Boots. Just follow the two paths available to you and defeat the bosses. After each boss is a button that raises the water in the White Orb chamber, when you have pressed both you can go get the White Orb through a long platforming section.



It isn't over though as you need to go to House of Ruth and have Ruth activate the Orb for you.



Pendant
Given by the princess when you're eligible for Ending #2, you can't confirm that it is a relic since you can't go back to a save point.

Character starts with 4HP and can get up to 50HP, 17HP is from items: Chicken Dinner (+2), Willow Nut (+4), Sushi (+6) and Elixir (+5). The rest is from boss drops and hidden Boss Hearts.

Camillo (+1 HP)
Found in Alexandria on the main game path, can't miss it.



Bubble Dragon (+1 HP)
Found in Alexandria on the main game path, can't miss it.



Mr. Arrey (+1 HP)
Found in Alexandria on the main game path, can't miss it.



General (+1 HP)
Found in Alexandria on the main game path, can't miss it.



Harpie (+1 HP)
Found in Agros Forest off the main path, after the 2nd save point you'll eventually come to a screen where you can go left or right, go left for this boss.



Flesh-Eater (+1 HP)
Found in Agros Forest on the main game path, can't miss it.



Frost Ape (+1 HP)
Found in Cave of the Great White Ape, the area is linear so you can't miss the boss, check the Area Guide.



Blue Serpent (+1 HP)
Found in Cave of Serpents on the main game path. Can't miss it.



Armor Shell (+1 HP)
Found in Cave of Serpents on the main game path. Can't miss it.



Twin Hydra (+1 HP)
Found in Castle Dungeon. The area is linear so can't miss it, check the Area Guide.



Chain Knight (+1 HP)
Found in Castle Entrance on the main game path. Can't miss it.



Rock Golem (+2 HP)
Found in Castle Entrance on the main game path. Can't miss it.



Blood Rose (+1 HP)
Found in Grand Hall on the main game path. Can't miss it.



Frog Knight (+1 HP)
Found in Grand Hall on the main game path. Can't miss it.



Cyclops (+1 HP)
Found in Castle Entrance. From the 1st save point go up and left instead of up and right, you'll need the Boomerang to activate the lever inside the wall. Also need Wing Boots.



Leviathan (+1 HP)
Found in Sunken Temple. Required to get the White Orb, check the Area Guide.



Donamazu (+1 HP)
Found in Sunken Temple. Required to get the White Orb, check the Area Guide.



Jail Guard (+1 HP)
Found in Castle Dungeon. The area is linear so can't miss it, check the Area Guide.



Bone Dragon (+1 HP)
Found in Torture Chambers. The area is linear so can't miss it, check the Area Guide.



Numb Flesh (+2 HP)
Found in Torture Chambers. The area is linear so can't miss it, check the Area Guide.



Dimensional (+1 HP)
Found in Crystal Tower. Check the Area Guide for location.



Crystal Golem (+1 HP)
Found in Crystal Tower. Check the Area Guide for location.



Defender (+1 HP)
Found in Windy Ruins on the main game path. Can't miss it.



Haunted Armor (+1 HP)
Found in Windy Ruins on the main game path. Can't miss it.



Bloody Mary (+1 HP)
Found in House of Ruth, needed to get Ruth's Key and activate the White Orb. Check the Area Guide.



Appolyon (+1 HP)
Found in Sorceror's Quarters. After the 1st save point you can go up and right or go all the way up, using the Summon Falcon magic you can go up and after a platforming section you'll reach another save point which leads to this boss.



Secret Boss Heart 1 (+0 HP) <- as of 1.05 this is correct, bug?
Found in House of Ruth inside the coded door which is located downstairs from the 1st save point, the code is found before Ruth fight and is:



After that you'll have to complete one of the hardest sections in the game to get the HP.



Secret Boss Heart 2 (+1 HP)
After finding the Museum Key above the 1st save point in Sunken Temple you can open the upstairs door in the Museum which leads to this heart.



Elixir (+5 HP)
After you beat the Crystal Tower and get the X-Sword the chest left of the entrance opens, you do not need to have X-Sword equipped for it to open.