The estimates in each section are guesstimates, and the work may take less or more time. We're currently 4 weeks in.
This is nearly done now! This first iteration of the mega arena has different wave types (normal, boss, night), special effects (weather, buffs), and some new items. I hope to develop it further in future updates - more effects, more arena-specific entities, and other things that spice it up.
β Bee lady entity (1-2 weeks)
She's done! She has 3 moves now: a floating honey bubble, a downward sting dash, and a horizontal sting dash. I plan to make the animation into a group one in the future and I've kept that in mind while making it :)
β Effects (1-2 weeks)

There are 4 weather effects in the arena now: stormy rain, tornadoes, magic distortion puffs, and moon night. Alongside these, we also have movement effects like low gravity, faster movement speed, and two tougher entities ones. I have ideas for more in the future.

β Riding broom (1 week)
Done! The outfit sprite work is finished and it works mechanically.
π¦ Core arena (1 week)
A lot has been done here, but what remains now:
Permanent rewards (outfit pieces, spells)
Optimizations and testing
Redoing the way loot works? (maybe partially)
π¦ New spells (1-2 weeks)

I've added a new spell, the Heart Shield! It differs from the Bubble Shield in these ways:
It only blocks in one direction, but it blocks physically (it behaves like a wall, entities can't walk past it)
It can be used more frequently, uses less energy
It has 100 HP (twice a Bubble Shield) and it replenishes its HP while not in use
Otherwise I've been testing and smoothing out the ultimate spells.
Didn't work too much on the next sub-region this time while I focused on the mega arena work. That said, I hope to make any fully finished new entities available in the mega arena so they'll be available before the full sub-region :)
π¦ Plant Spitter entity (1-2 weeks)
I worked a bit on the animation here - it's nearly fully done now, but as with the bee ladies the intent is to make a group one eventually so it's set up for that future work too.
β¬ Spider lady entity (1-2 weeks)
Didn't get to work on these this time
β¬ UFO / alien special/miniboss entity (1-2 weeks)
β¬ Level design (1-2 weeks)
β¬ Farming / minigame (1-2 weeks)
β¬ NPC quest (1-2 weeks)
More bugfixes and improvements - for example, spells show their cooldowns after use and spamming spells no longer resets the cooldown, and the minimap has region titles.
I've also had some time to work on outfit pieces - the bunny ears should be done now, and I'm working on the skinsuit outfit piece but I expect that one to take a while.
That's it for this update - as usual I'll aim for another progress update in two weeks