So I have played Dx's level and here is my opinion so far:

The level features quite some interesting challenges most of them including rolling rocks but also some hurt events and quite good enemy placement. Some of the rolling rocks are effected by wind and belts which might be weird at first since the level doesn't give you any hints when to expect wind and belts but you will get used too it and will provide some good challenge. Enemies can be quite annoying because the big boxes will block most of your shots which actually add to the challenge since the enemies are easy in jj2. The EC is original but some places can be really dull. Although it looks decent enough it's not anything special. Also the water looks buggy in my opinion. All of this is driven by a really simple story but it's just one SP level so it's not the most important thing.