Working demo version

This demo shows basic gameplay on a test level.
No sound fx yet, music is just a placeholder from AKG music samples (it takes a good share of CPU cycles, casuing slowdown in some moments).
Controls are keyboard arrows left and right, Z and X for running/jump.
The color bars on screen border are just for debugging, they show the time taken for each part of the game loop.

This is the state of development as of September, 2022.