Gameplay Flow

Polished the UI for menus a bit more so it's more clear what everything does and what everything means.

Changed how the game mode works, instead of the same waves appearing everytime you play the game, now the waves are procedurally generated and they scale better in difficulty.

Trimmed the amount of difficulties in the game, now there's only Easy/Normal/Hard

Enemies are pretty buggy right now because of the change in difficulty. They'll be fixed and rebalanced in a couple of days.