Just achieve a stable production of the sting science, and working on the ring one. IMO, Rubia is one of the best planet mods and I like the way you make these early research like a guide and let them run by throw them away and count in trigger so they don't block the vanilla science, plus you provide a recipe as a tiny free mall. I have only a few suggest just wish you to take a look, mostly graphic.

The Trashsteroids seems a little weird because of their transparency. Now they look like bubbles and as they got killed, they suddenly turned back to rock. I would like to see it keep solid for the all the time like normal asteroids. Or you can just using shadow as a hint that the Trashsteroids are coming.

And cliffs & rocks! I feel this planet is too flat and some cliffs may make it looks nicer.

And Crapapulta...I see the discussion, but I wish it can shoot something. It plays a pretty important role here, so I believe it deserve a better graphic. Probably just make some fake random projectiles or random blur effects as a part of its own animation and loop it when it is working?

Thank you for your feedback. We’re glad you had a good time with Rubia.

To the specific graphics:
1) The issue with no transparency is that they spawn at arbitrary spots on the surface. Imagine big opaque rocks popping into existence on screen at random spots every couple of seconds when looking at Rubia. I added the transparency because it was very distracting.

2) I always wanted cliffs and rocks. I was ultimately limitted by my undersranding of map generation, and too few people capable of explaining how to implement it in factorio. After a few weeks of trying, I gave up. If you look through the mod files, you will find many more assets for trash and rocks to be placed on Rubia’s surface, commented out because I could not get them to spawn without breaking other things.

3) The crapapult issue is tied to how factorio implements it. The crapapult animation is a working visualization + sprite sheet for the crapapult. There are no events raised either during crafting, so making it look like it is actually shooting just is not feasible in the factorio engine. The machine can randomly stop on any sprite in its sheet indefinitely, so a sprite that includes shooting/blur could stay there as a static image. Sorry, it just doesn’t work with the 2.0 factorio engine.

Just out of curiosity, regarding the crapapult, would it not be possible to use the delivery cannon from SE? I don't know if it is possible to change the interface where you have to give it a coordinate since on Rubia's case it would work differently so different triggers (like you said)

The crapapult is a furnace. Delivery canons are not. The crapapult cannot be changed to a different prototype.

It looks like Earendel manually iterates over every delivery cannon every tick to manually check its status, and do its own logic. Delivery cannon has several restrictions levied on it to make that happen. Doing an equivalent strategy will not work for crapapults, which are furnaces and much more spammable.

Just out of curiosity, as you said the crapapult is a furnace. The furnace itself can stop at any frame and the glow just disappeared and won't stay there as a static image. I thought there is another layer of the animation?

There are two layers of animation. First is a sprite sheet for the machine (eg basic movements like assemblers moving shafts…), and a working visualization (like the glow of a furnace). Iirc, both animations can take two layers each. However, the base animation and working visualization do not talk to each other.

See the crafting machine graphics set: https://lua-api.factorio.com/latest/types/CraftingMachineGraphicsSet.html

Perhaps a more clever modder knows how to game the engine better than I, but chatting with the other modders, we couldn’t figure out something decent.

Alright, just asking one more thing. I have just reached the stage to produce the circle science pack and it request iron bacteria. There is another iron bacteria cycle recipe from Planet Muria which need few extra oxygen and produce more. I can make oxygen on Rubia so that I wish you can remove the surface limit of that recipe as well. Kind of compability stuff, I asked Muria's creator and he told me to ask you.

Please open a new thread for that query to track that discussion more easily with others who may have the same suggestion.