Why is my game preview so slow?

I'm making a game prototype for my college project however when I run it the preview gets slower and slower and the controls become more delayed.

Granted the level I made is quite long but my class mates have also made games with multiple level some of which are just as long.

Could it be because I'm using my laptop? Is my level too big?

If anyone has any ideas please let me know.

It could be many things. Your preview browser might not be able to handle the level size, there may be an object that is constantly being created without being destroyed(an overload of object spawn), it might be that your game is constantly saving(saving game progress) without having the objects, that are not needed to be saved, have the "No Save" behavior(because there are so many objects in the game, or instances of an object), it could be that your level is just too big, or maybe your computer is just too slow. It shouldn't really be that your computer is too slow, unless it is kinda old, or just very low-end, because usually even low-end devices can run the projects very well. It could also be that your sprites have too large of a resolution.

Hope that helps! Let me know how it goes, and if you still can't figure it out, maybe screenshot the level so I might be able to help a bit more.

AstraRune

Try running the game in debug mode (Ctrl-F4)

Check two things -

1. the number of objects instances on the left panel. If you are spawning lots of objects and not destroying them, you'll see it.

2. and the number of collision checks. Too many collision checks (over a thousand per tick or more) will slow the game down.