@versioneight With a screenshot of your behaviors we can have a more specified discussion, but off the bat a "set behavior state" behavior (in behavior tab "custom") will probably get you to where you want to be.
Say you want the item buff to last 30 seconds: after the buff trigger, add a "timer" behavior. Attach a "set behavior state" and make it turn off the behavior tree inflicting the buff (setting the behavior state to "off" on any behavior in a behavior tree will stop all subsequent behaviors from triggering as well.)
There's some complications here like: 1. if the buff was a flat value addition, turning of behaviors won't then change values back (in that case you could reverse the effect by storing the buff value and adding when buffed, subtracting when not. 2. You will need to turn the behavior tree you turned off back on so that it's ready to receive a subsequent buff (can be done with the existing timer or maybe when the object is picked up or whatever).
I feel like I'm not making a ton of sense but if you screenshot the behavior tree I promise to be a little more coherent xD

Level design progress. Other than trees that might be as far as it goes. A lot of second guessing myself in the beginning but live and learn.

I'll post again probably after I have a walk cycle animate

@themerpygirl I see. I'm nobody just a casual user and as such won't speak for anyone. My subjective opinion is a little header flare is similar to using stock assets to improve the UX of a PowerPoint presentation, team email, newsletter...
I agree the use of AI defeats the purpose of creative spaces and compromises the integrity of an environment as a whole. We need to be careful how much we pretend we don't see it.
If there's a halfway point we could reach I would hope it's that there's places where things are more and less appropriate. We're talking about a very small team with a very high volume of tasks on their plate with an active beta and a roadmap that's a mile long.
I have a design degree and love the creative space like it's sacred but I have to admit; this feels like an overworked team cutting a corner to give us a little more than literal black text on white because they are strapped for time with college, life and work that actually makes money (they do this at a loss just clinging to the hope the world will see the vast potential someday)

@versioneight Apologies for replying four days later I was out for the weekend.
I now see your issue; It would seem the "ignore bullets" behavior was designed for scene objects where you want to ignore bullets permanently. In the forum someone said disabling it with a "set behavior state" should also disable the effect but that isn't working for me so I used tags to work around it:
Instead of having the collision with the power-up set a "ignore bullets" behavior; you can have the bullets set to collide with a specific tag (I see you're using tags already). When the player collides with the invincibility item, use a "modify tags" behavior to disable or change the assigned tag. This will make bullets no longer impact. Next, add a timer attached to another "modify tag" to re-set the tag to normal making bullets hit again.
This tag logic should be adaptable for applying various effects. If you need a screen shot or have further questions let me now. I honestly enjoy solving problems and I'm learning as well so this is all good stuff :)

@versioneight P.S. you might want to have a tag for bullet collisions specifically. Found out the hard way things get screwy if you start trying to use the same tags for more than one function

@KrystalYee Having the same audio file played at slightly adjusted and varied pitch values for variety is one of the coolest fast UX tricks I've seen.
Thank you a million for all for of the audio advancements. Being able to tweak-test-tweak-test-tweak-test with no latency on compile until the audio trigger feels correct is one of the many reason I wouldn't be anywhere else.
You all are the best!

@themerpygirl Characters and sets are looking really good!

Day 2 I have the framework for the fishing portion mostly functional. The theme is time dilation.
Our character who spent his life as a space trucker decides he doesn't like society and orbits the event horizon of a super massive black hole in order to speed up time so he can go fishing on a newly terraformed planet millions of years into the future after life has evolved.
The first time is easy. You go to the planet, fish until there's enough food in stock to travel back and orbit the black hole again.
Second time something is wrong... millions of years have passed and some of the stars you used to navigate and fuel scoop aren't there anymore. If you can't find a navigation path back, you starve.

@KrystalYee You're too kind :) I'll be putting more work into it before posting but expect it up soon-ish

@Murtaza Thanks! I tried the free copy of Affinity Photo 2 you mentioned but found Pixaki is still smoother for knocking out a lot of stuff. Photo is just built too heavy for simple work

@Unisan

@mr_monkey If you're using the "joystick controlled" behavior for your character sprite, there's a parameter for max speed and a parameter for acceleration within the behavior. If you raise the max speed and lower the acceleration percentage you should be able to find a sweet spot where your sprite speeds up at a rate you find desirable

@mr_monkey This tutorial will give you the base knowledge for creating a level. From there it's really just playtesting and adjusting.