Welcome to the forums, and to the wonderful hobby that is brickfilming! I like your first test, that transformation/green whirlwind effect thingie looked cool. There are two beginner tips that I would give.

First off, make sure your camera doesn't move. (Unless you want to have camera movement in a shot, of course.) If you watch back your Dark Souls test, you can see that in the beginning the camera slowwwly drifts up and to the left. Taping down your camera or using something like sticky tack can help a lot.

The second tip is reducing light flicker. There's a lot of changes in brightness between one frame and the next, and this can be very distracting. On the camera end, make sure that automatic settings (like brightness, contrast, shutter speed, white balance) are all set to manual. How to do this depends on your camera and software. Also, make sure to block out sunlight and other light sources from your set as much as possible. Ideally, only the lamp/lamps you use to light the set should be shining on the set. Sunlight especially changes a lot from minute to minute, and it can be very tricky to work with.

Hope this helps you, and I hope to see more from you!