How do I fix slowed down preformance?

Hello I've been developing a game for a while now and recently i noticed that the game overtime slows down a LOT. Because the game is pretty long it is fast at the beginning and at the end its wayyy slower then when you start. So i hope some people can help me with this and if you know somebody that knows a lot about construct 2 show them this post and please share this post because i need to finish this game fast and i think that this game is gonna be pretty good unlike my previous games.

There are a million possible reasons why this may happen and without seeing your project it's impossible to tell.

The most common mistake is creating lots of objects over time and not destroying them. Run the game in Debug Mode, play it a bit and check the list of objects on the left, see if there are any unusually big numbers there.