I have tested both projects and both of them run fine on my computers. However, if you examine the debugging panels (press F11 after running the level) you will notice that the A7 level has more polygons, which explains why it runs slower on your laptop.

The solution is simple: create the level from scratch using A7's Wed and keep an eye on the polygon count. Don't subtract the holes from the ground, as I did (this increases the number of rendered polygons a lot) - try to create the levels out of models.