Update 1.6 for Hellhole Island has finally been released! This update adds a new boss, a bunch of new items, and QoL improvements. Here is the full changelog (Beware, it's large):

Additions:

• Some new soundtracks by quabanosPL
• Added Jeff boss fight, he is Joe's brother and he drops ukrainium
• Added new drops from some of the boss fights in hellhole mode
• Added trainwreck mode, activated by setting"game too hard" as the world seed
• Added new default player skin and new player animations
• Added emotes
• Added custom skin support, replacing gender selection on world creation, it affects every world in the game now
• Added bestiary
• Added 10 world icons to select from
• Added 4 new accesories
• Added new enemies
• Added 7 new achievements
• Added cauldron, which allows brewing potions
• Added potions, created by combining some ingredients in a cauldron. Mess around a bit to discover new ones!
• Added slime floor, which slows down the player, but increases slime speed
• Added new alchemy ingredients, dropped from mobs
• Added skull wearable
• Added 2 rare weapons that have a less than 1% chance to drop
• Added flowers in item form
• Added new world generator decoration, such as lakes (finally back!) and a boat
• Added silver ore, it's in a tier between iron and gold now
• Added ukrainium, drops from Jeff
• Added aquanium armor and tools
• Added new nouns and adjectives to world name generator
• Added structure blocks
• Added search into creative mode inventory
• Added a new death screen
• Added Ukrainian flag, crafted with iron bars, paper, wool and ukrainium
• Added locked chests around the map (these contain accesories and other goods!) and the ability to lock your own chests
• Added new rushnyk/vyshyvanka carpet
• Added Discord activity for the game
• Added some new settings
• Added a new font for GUI titles
• Added tooltips for crafting menu
• Added splash texts on main menu

Changes/Minor features:

• Titanium drill now has more tool power, and post-Ore Golem/Squarium-related blocks can be only destroyed with it
• Fishing crates are now way more common
• Updated armor sprites
• Firesword swing is now faster and its base damage has been increased from 27 to 29
• Decreased dashing cooldown
• Increased squarium drop chances
• Updated player enemy collision hitbox
• Added old version warning in world list
• Gold ore is now slightly rarer, and iron and copper are more common on the island
• Updated textures
• Solid aquanium now emits light
• Pyrium/aquanium items/armor and squarium now glow in the dark
• Updated health bar appearances
• Updated a few item tooltips
• Campfire now damages player and enemies on touch
• Changes to creative mode tabs (reorganization and changed item icons)
• Decreased amounts of blocks generated
• Fixed death logic
• Pain void is now worthless and doesn't sell for anything
• Standard wood blocks now have been renamed to fit the rest of the wooden items
• Updated sussy quiver crafting recipe
• Advanced options menu is now inaccessible when hardocre mode is selected
• Pain void can now be crafted
• Step sound play interval is no longer affected by worn accesories
• Food items now have a cooldown
• Fixed dashing length
• Removed ore golem shoot particle
• Slightly extended pickup range
• Item achievements are now always granted when the item in interest is in the player's inventory
• Bosses no longer count towards Hunter achievement
• Floor sprites are now offset a bit
• Some enemies have slightly more health
• Updated Rock Golem AI
• Garden gnomes and angry fireflies are now rarer
• Tooltip is now closer to cursor
• Beds now always set spawn position close to them
• Updated ruined house
• New main menu background
• Reorganized main menu
• Increased Magma Monster hitbox
• Beds can no longer be used in the mines
• Beds now always set spawn position close to them
• Time now passes 2X faster in the mines
• Leaf blocks now break instantly, not dropping anything
• Pain void no longer spawns in Hellhole mode inventory
• New achievement notification design
• Fixed camera at the left and right edges of the map
• Critical strikes are now slightly rarer
• Increased sniper square shooter enemy speed
• Added sounds for water-related actions
• Travelling merchants sell more items
• Default stone tools no longer drop, no matter what the world settings are
• Doubled amount of slots in crafting menu
• Reduced spawned enemy cap
• Life flowers are now twice as common, but can only spawn at night
• Fixed an issue where money would not be attracted to player like all other items
• Furnace now emits light
• Allow picking out chest items only when there is space in the inventory
• Added tooltip for interactable blocks and travelling merchants, suggesting which key to press
• Travelling merchants now stop when shop is opened
• Enemies with ranged attacks now start attacking when close to player
• Fixed a bug related to picking out items
• Defense is more effective in Survival mode
• All bows now pierce enemies and arrows are faster
• Item tooltips are simplified when inventory is closed
• Worlds now default to keeping player inventory in Survival mode
• Life flower now increases health by 5
• Squarium Altar and Coin Machine are now immune to explosions
• Player fireballs now have a homing property like their enemy counterpart
• Evergreen and birch wood floors are now craftable
• Enemies now have immunity frames
• Immunity frames are now shorter
• Items should properly follow player at shore of the island
• Rock golem now drops from 8 to 20 of the tier 1 ores instead of from 9 to 19
• Angry fireflies now have a rage state under 50% health
• Magma Monster's explosions now spawn further from him
• Trees now yield more wood, and take fewer hits to cut off
• Health regeneration now works even without red necklace accesory, and when it's worn 5 health is regenerated instead of 1, and it also takes 1 less second to do so
• Enemy hearts now glow in the dark
• Pickup items are now larger
• Pickup items should no longer get stuck in any blocks
• Increased Super Shooter base damage
• Chromium anvil now acts as an extension of the regular iron anvil
• Changed chromium anvil recipe

Technical changes/additions:

• Added boss defeat flags
• Reworked damage system with damage source info and better handling of enemy knockback
• Added status effects
• Dragged inventory items are now handled differently
• Improved quite a lot of the code
• New random drop chance calculation algorithm, whic supports decimals as dividers

Have fun playing the game!