Very ambitious jam project for just a solo developer! If I understand correctly you re-used a certain amount of code and assets from previous games but you also spend a lot of time on things people might take for granted, such as the custom shader work.
It has just the right amount of difficulty for me. I was able to figure out crafting and building in time, without getting any of the values at 100% and was able to beat the game.
It would've been easier to gather resources with an aiming dot. Also the lag spikes made it a bit difficult to play, because after the lag spike I often ended up in a random viewing rotation which was disorientating.
Perhaps some more audio cues and audio feedback would be a quick and easy improvement to the game's experience.
Overall, well done with combining all the systems and shader work, I hope you will run into less technical issues next time!