For now I tend to a slight increase, but the implementation is tricky and must be discussed. In that the main problem is located and if we find a good way, I would be completely fine with a higher increase.

Shrinking the buttons in width is only enough for a slight increase and will require customs buttons to be redrawn.

2 rows with a lower heigth would still have a limit of 16, would require redrawing of all custom buttons and would introduce the Lix "korean washing machine" effect of overloading the UI with tons of buttons.

The  "scroll left" / "scroll right" idea seems more future-oriented to me, while also avoiding the "korean washing machine" effect. A limit might still be desirable when the skill type number increases even more over time and I think nobody here wants to scroll through a huge list.
This of course has the disadvantage of not displaying everything at the same time. Testing needs to be done here I think.......

Re-solved the 2 updated levels.

Solved the 3 levels and these are pretty nice little puzzles indeed!    I might have a feeling my solution to the 2nd one is a backroute though.

Feel free to add more levels over the time when your brother gets new level ideas!

The tileset looks and plays amazing!

I think some really good levels can be made from this and a set with all the standard letters and numbers is always useful. This would be a worthy addition to the standard library!

I've attached my solutions.

In regards to the prize, I would like to donate it to the upkeep of this forum, assuming that is possible.

Alright, the prize has been sent!

Blood born has been readded and I attached my solution.

V 6.3 is out!

The following levels have received a backroute fix:

- 5 15 (a digger is now a pick-up skill)

V 6.2 is out!

The following levels have received a backroute fix:

- 5 15 (added some steel)