v0.4

Extra shots and hearts are now increased with coins to collect. Too important to miss, thus they are fragmented.

6 new shots have been added, and yet more fiddling with how shots are drawn to encourage a fresh selection when replaying.

Also, lots of optimisation, bug fixes, and quality of life changes.

Apologies for the new monster: the shooter. Once I have a lot more chunks I'll be able to balance what gets drawn to play with.