As discussed in #5041 and #5124 we could add a new (operational non-ingame-visual) material layer to implement new materials like for example ice, sand, bouncy-slime, glue, ground-booster, zero-G and whatever you can think of into ddnet. This would allow for a lot new gameplay. This is not limited to solid/unhookable blocks
The basics (and ice) are already ready as PR for vanilla teeworlds and I would port them to ddnet if you are interested. I would also remove the CustomLayer, which...