I had a look at your Halo and Zelda files. The reason your grenade animation doesn't play in your Halo game is because your tagged animations are interfering with it. You change to the grenade animation, and the Platform behavior automatically switches it back to something else that's tagged in the next frame. Solution: Don't use tagged animations for Platform behavior. Set the Standing, Running, and Jumping animations using events.
Another thing I noticed in both of those games is that you aren't using a separate hitbox for your player sprite. If you don't then you will run into weird problems. Notice how Link sort of flops up and down on the ground when he runs? And how Master Chief crouches in mid-air and then falls to the ground? Those are the kinds of things that you will run into, along with getting stuck on platforms by your extremities and teleporting through objects. You need to have an invisible rectangular hitbox that doesn't ever change size to use as your Platform Behavior, and then place your player sprite on top of it in order to get solid results.
Take a look at my Platform School tutorials:viewtopic.php?f=8&t=2154
They will give you the basics that you need in order to make a platform game. They don't work with the latest version of Construct, though. You will need version 0.98.9, which you can find here:http://sourceforge.net/projects/constru ... e/download
There is some old info in those tutorials but you will at least have a basic understanding of what to do after going through them.