vidtest
Don't be too discouraged about speed. You can still do some interesting things. Here is something I did called "
vidtest", to test video on a K3 back in October of last year (see attached file). This is just a binary executable that runs on a K3.
I need to clean up the C source code before I publish it (being a "test framework", it contains much more obsolete "commented out" code than current active code).
UPDATE: It has been cleaned up and published as the "sparkle" demo" in another thread for C demo programs.
The K4 and Touch have much faster display update algorithms, so I am looking forward to programming them in C with performance as good as or better than how this video test program runs on the K3.
When you run this program on a K3, you can see what I was talking about when I mentioned the "time domain artifacts" from the kernel-mode display driver eink update algorithms.
Do you see how fast those pixels are being updated in 4-bit (600 pixel wide) mode? I am looking forward to seeing them updated using Conway's Life algorithm! 
EDIT: The choice of programming language is rarely the problem. You just need to "think differently" and find a better algorithm. You should read Jon Bentley's nice little "Programming Pearls" books. They are quick reads and wonderful sources of software inspiration! 
