Welcome to RTVFX! 
That’s a great start already, good job!
First off, I’d encourage looking around the website and searching for these things. You’ll find a lot of cool stuff! Erb’s sketchbook is great start to look at stylized stuff for example. Also check out the resources section. Check out pinterest for a lot of effect references you’re looking for. Record game footage, build your own library!
For your effect, everything feels a bit linear and slow.
At the start, the slashed feel very off timed and don’t match the animation. It throws you off and feels awkward and “wrong” to look at (at least to me)
At the end, she swigs from down to up and your slash spawns from up to down. It can work if done with more care and with more elements I think, but here it again throws you off and feels wrong.
Play around with timings, try something weird, something explosive with the keys. The erosion also feels quite slow and linear at the end.
Also I’d suggest trying Screen2GIF or OBS to record your videos, it’s free and very customization with great quality! You can also try ShareX.
Take a stroll around here, get cozy and make some friends! Post things and get feedback. There’s so many threads with amazing knowledge around here already, too.