hey there! Guess what? I've also programmed on GMS2. I know it's not easy to do pathfinding, so congratulations! Your game is fun and there are some points you could improve.
- Controls: Having actions and movement shared between mouse and keyboard can work, but having mouse interaction and another action on space isn't practical.
- I like the idea of building small towers to defend against monsters of different colors. It's a great concept.
- You should make it clearer to the player that they can create towers by pressing space. Personally, I noticed it after 3 runs.
- I love your game! Adding some music would have been great to immerse me more in defending my base.
Keep up the good work; I really enjoyed playing this game. <3