v0.999991

This is quality of life update, as well as the return of the demo.

• Added a hot tiles effect to the retreating lava.
• Gate chunks now have one altar at the start of them. These chunks were meant to slow the player down, but without altars they upset the pacing. This reduces the difficulty of some later levels but hopefully remains a challenge.
• Bug fixes.

Work continues on the next boss. As well as plans for yet another mechanic, and more chunks.