Major update to the prototype

New Enemy: Aircraft unit

- spawn above tower

- rush to player

- deal damage based on it's current hp

UI: Level Selection Menu

- 8 level are made with increasing dificulty

- when level complete, green dot will appear as indicator (WIP)

Design Assets Implementation:

- player, enemies, projectile have their design implemented

- parallax background in the levels

- Map design for level selection menu

To Do list:

- add animation, sfx, and bgm

-  balance damage/health of player and enemies

- save progress function

- improve player aiming/shooting function