I'm a gymnast, next to that I enjoy doing some trampoline stuff. For your backflip on the ground, I'd remove that little step you do backwards before jumping, it only gives you some backwards speed, while you clearly don't jump high enough, focus on that.
And uh, landing a double front flip is pretty sick, best I can do with double front is landing on my back, landed on my neck once so I'm not a fan of it.
Your forward corkscrew looks pretty cool too, I can only do it backwards, no idea why.
Also, I'm not an lmod in here, but I'm not sure whether this is the correct place and stuff, doesn't off-topic need discussable stuff.