How do I define why my is slow?

Hello!

I have published my platformer. It is in scratch mode, however I have faced bug with it.

It is strange. My game starts to "freeze" and becomes slow since the half of the level.

In the end one second lasts for 3. It creates really bad experience.

tinyurl.com/zb235t7

C2 shows it is 17 MB in download, uses 99MB of Memory and has 245 Events

How can I find the "slow" part and fix it?

Thank you.

Have you tried using the Profiler in the Debugger? If you've grouped your code, it's very easy to find offending chunks.

When I start game with the debugger - it works very slow since the beginning ))

In the top-right of the debugger panel you'll see 'Watch' and 'Profile' - click Profile. For a start it'll run faster when in Profiling mode - and it'll give you feedback on what part of the code is using what % of CPU cycles.