Just felt the need to write something...
Done sprites optimization. The flames are now compiled sprites. The hero is done with compressed and a few clippable standard sprites. Stance animation frames are fully compressed sprites (two sets: right and left), jump is in two versions (and both in 2 sets) because it needs some clipping and fall animation frames are only standard sprites and only facing one direction (flipping before drawing when needed) because the slowdown won't affect the gameplay as it's already gameover.
I wanted to use compiled sprites instead of compressed ones but I run out of 16kb for the sprites... And found it pretty shocking... I mean this was what... about 7 animation frames although more like 12 because of the preflipping... And already so much memory... However the sprites are around 32x40 pixels so they're quite big I guess... Couldn't do it for 64kb...
After this optimizations the game runs most of the time in 25fps. It slows down a frame when needs to clip the jumping sprite or when all flames are fired and all effects (rain etc) are turned on. But I'm really curious if using this:
https://enterpriseforever.com/programming/video-config-that-allows-to-draw-sprites-vertically/ with the triple buffering could get it to run in 50fps... But that would need a lot of refactoring... and I don't have the time... I'd need to have it more-or-less finished by the last day of September (with additional 2-3 weeks for bugfixing) and I still haven't touched the gfx and msx much...