[M] You shouldn't be able to stand on invisible blocks, before you bumped them
the roof
[M] Implement Unisolid type for tiles (where collisions from below are ignored).
+[M] Menu doesn't jump titles, and doesn't seem to like having menu entries created
+ after initialization.
[L] Allow any object to be inside of a [?] box, ie. trampoline or badguy
- Not sure if this would be gameplay wise.