@neauoire I've been working (slowly) on compiling Fortran to Uxn, and my conclusion is that the main barrier to do this in a usable way is the lack of support for malloc and free.
This has nothing to do with the number of instructions per se, or the memory size. Of course we can implement this in the machine code, but at a considerable cost in instructions and performance. I feel that a really frugal VM should support dynamic allocation because it allows better use of the memory.