KatFS Alpha Devlog #9 (March 2025)

Hello all! Presenting the monthly Alpha Devlog for March 2025! So, what did this month bring us? We have the new interaction-based grab-and-move mechanic, we have plenty of devices, and we have a little extra teaser if you stick till the end. ;)

So let's get started!

GRAB-AND-MOVE

In last month's devlog, I mentioned the new contextual interaction paradigm that KatFS would be adopting and how the "grab and move" interaction would be changed to work with it. Quick refresher, contextual interactions work by having special triggers that "select" an interaction while the player is inside it, which can then be activated by pressing the interact key. The "grab and move" interaction is the one where Kalia grabs onto an object and can then move it around, which is present in the pre-alpha demo and required for some puzzles.

This interaction has now been reworked for the alpha, not only in how it is presented and initiated, but also in how it works:

So what's different from pre-alpha? First, there's the new interaction prompt that should make it much clearer when an object is able to be moved this way. It's a bit hard to see due to the GIF compression, but objects that can be grabbed and moved will also feature visible affordances in the way of the handles on their sides. If you're not aware with the concept of "affordance", in a nutshell it refers to an object's ability to suggest its intended use by its design, such as a big shiny button inviting the user to press it.

In the pre-alpha, this interaction was checked by detecting if the player was directly touching the object's main collider, which was an awkward way to achieve it. You had to bump Kalia into the object and press the button to grab onto it, and paired with the lack of prompt it was a hit or miss whether the interaction would work or not. The alpha now uses dedicated interaction trigger zones like any other contextual interaction, giving it a much greater detection area. A related improvement is also found in detecting which orientation Kalia should face when she's grabbing an object: in the pre-alpha, a heuristic was used to detect where Kalia was in relation to the object, but in the current build, I have made it so each grab trigger can have a direction assigned to it, completely eliminating edge cases. Kalia will also "snap" to the pivot of the grab trigger she's activated, ensuring she's never grabbing the object from an awkward position.

Finally, an improvement that's difficult to showcase through GIFs, but will definitely be noticeable to those that played the pre-alpha and fiddled with moving objects for a while. The new build uses a 2D joint to move objects, rather than moving them by their RigidBody2D by copying the player's movements. What this means is that the player now "sticks" properly to the grabbed object and effectively moves Kalia and the object as a single entity. In the pre-alpha, it was possible to drift away from the grabbed object in certain situations, which would cancel the interaction and require the player to initiate it again.

FANCY DEVICES

March has seen the implementation of many of the device functions for the facility chapter (and beyond). Some of these features should be familiar from the pre-alpha demo, while others are completely new. You may also remember some of the assets that were shown in the February update, now you'll be seeing them in action!

First, a rather simple feature that emerged from a need to allow players to experiment while solving certain puzzles without soft-locking themselves: an item respawner! In KatFS, puzzles may require for specific items to be destroyed as part of the solution, which presents a very obvious issue in that if the object gets destroyed before the puzzle can be finished, the player is left without the required resources. The solution, just restore the object after it is destroyed! These conveyor belts come in handy, delivering a new crate of volatile materials for you to try this puzzle again!

Seems simple, but under the hood the same instance is being moved and restored to its "factory configuration", which is handy in saving performance and also makes it easier to save and load level states around these.

You can also see the new heat sensors in action in the GIF above. These are being rebranded as "heat converters" and are supposed to be devices that can convert heat energy directly into the magical energy used to power the devices around the ancient facility and lost city. Functionally for the player, however, they operate the same as the sensors in the demo. Some of these devices only require an initial surge of heat to activate and will remain on indefinitely, indicated by their display closing. Others will require a constant source of heat to remain powered, indicated by the display remaining visible and merely changing to display the current status.

(I'm also considering giving the display a red/green tint instead of yellow to better showcase its state.)

The good old pressure plates have also gotten a facelift. Otherwise, they still operate essentially the same way the have in the pre-alpha demo.

And now for my favorite of the bunch, and also a brand new device! The battery blocks are bulky objects made to hold magical charge which can then be slotted into the appropriate ports to power devices. Batteries and their supporting elements are identifiable by their blue glow instead of the typical yellow. Their purpose in gameplay is similar to that of pressure plates, but they also present additional constraints, such as the need for batteries to be charged first, and battery slots strictly requiring batteries while pressure plates can accept any object heavy enough (including batteries, or even Kalia herself!).

(I'm particularly proud of how I implemented the system for slotting and unslotting batteries in their port by doing a little hack around the "grab-and-move" interaction)

Finally, showcasing the door animations because I just think they're neat:

AND NOW FOR SOMETHING COMPLETELY DIFFERENT

I did mention a "teaser" in the beginning of the devlog, didn't I? While Kalia and the Fire Staff will definitely be remaining my main project until it is finished, I've been wanting to delve into a side project for some time now, and lately have been ramping up the conceptualization for it, to the point I'm ready to begin working on it alongside KatFS.

It's still early for this side project and therefore not many details to share yet, but I can at least hint at how it's shaping up: It will be a 2D platformer with a focus on puzzles and three playable characters. It will be developed as a joint project between myself and my great friend Diantha Crystal, set in one of her amazing settings and featuring her characters. In fact, let me go ahead and reveal the three protagonists of this side project, as drawn by Diantha herself:

Why embark on a side project though? While I want Kalia and the Fire Staff to remain my focus, I've been feeling the need to diversify my gamedev work slightly in order to avoid burnout and create opportunities for cross-pollination between the two. This is a project I've already been planning to do after KatFS, I'm just starting it earlier.

I expect this project to be simpler than KatFS and therefore not take as long as that game to develop, and Diantha's stake/help in it will also help tremendously. For now, the game's concept is still being formed and prototyping has yet to begin, but you can expect more info on it eventually. And if you're only here for Kalia, do not worry as development on her game will continue and I do have some interesting plans for her this year as well!

And that shall be it for March! But before we go, I have one last thing to showcase. A comparison between the first chapter of the pre-alpha demo and the facility chapter in the alpha as it currently stands. While the pre-alpha iteration of the facility was slightly larger, most of it was empty space due to the larger level grid forcing everything to be unnecessarily big. The new facility chapter is much more compact and content-dense, without long sections of just running from one place to the next. Except the alpha iteration of the facility is just the first half! So the complete facility chapter should be roughly twice as long as the demo one! And there are seven more chapters planned for the game, some of which will be even larger... 

See ya next time! :P