Much bug fixes and cleanup

Took several tweaks, but there is now a fixed and enhanced version uploaded.

• Fix crashing!
• Nicer keyboard controls
• Attempt at mouse controls (works on mobile but a bit fiddly, will need to rework this)
• Level select!
• Shadows!
• Removed the low pixel filter as it made scaling annoying and normal text difficult to read
• Options for screen shake and mouse sensitivity