Nicotine Nice platform game. The player controls feel pretty good. I like the unlockable door. So you can hide your key somewhere in the level and the player needs to find it to continue.
The levels didnt unlock beyond level2. Not sure if thats a bug or you only made 2 levels to far?
I did notice some lag in level 2. At first the level has no lag, but It seemed like the longer you stay in the level, gradually it started to slow down and become laggy.
Check the number of objects in the level using the debugger. Does the number of objects stay constant? Or does is increase?
I had this same problem with my game a while back and I discovered it was because I had an event that needed a 'trigger once while true'. Without that it kept creating some objects in the layout, and eventually so many were created that the game slowed down... maybe you have the same situation in your game?