New level & quality of life update

Hello everyone! We made a small little post-jam update for the game, adding a new level and making some quality of life improvements.

• Added level 5.
• Made levels 2 and 4 a bit easier by removing some spikes in some areas.
• The player now jumps a bit higher and moves slightly slower.
• The threshold for fall damage has been increased, making it less punishing.
• Progress is now being saved, and clicking "Play" will take you to the level you unlocked last, or the first level if you just completed the entire game.
• Added a level select screen.
• Added a pause menu.
• Fixed a bug where the bubble sprite remained visible even after death.
• The bubble pop effect now stays the place the bubble popped, instead of following the player's position.