Good to know man! Wish you luck on the project, if you need any ideas on how to make something work you can ask me as well (but only ideas since I don't use Scratch, but I can maybe transfer the logic from engine to engine). Don't forget to tell me once you're done so I can test it!
If you want ideas on how to make the peashooter fire only when they see a zombie, I recommend you this: This is only how I made it but if you see Scratch can't do it then it's ok if you got another solution:
- Create a lane object for each lane, so when you place a peashooter, it recognizes the lane it is on (as well as the zombies that are created on that lane)
- Make the peashooter analice if there's a zombie on the same lane they are on (You maybe can do this so the peashooter doesn't fire unless the peashooter and the zombie are overlapping the same lane).
And I didn't add this on my game but as an extra...
- Also make the peashooter not to fire unless there is a zombie on the lane whose X coordinate is higher than that of the peashooter. If you do it right, the peashooter won't shoot if there's just a zombie behind them and no zombies in front of it, just like the og PvZ. As I said before, I didn't add this into my game but I did smth similar for PvZ Night with the puffshrooms and it worked fine.