1 01 - Easy and good start. The only thing I could criticise is maybe that it look a bit blocky and could use a few more decoration on those large bricks.
1 02 - Also a very good easy level, which also looks as if it comes straight out of the original game.
1 03 - 2 things could maybe be improved: Again a bit more decoration on the dirst side and the cross at the very left makes it a bit unclear that it actually turns the lems around. Maybe making it stand out a little more could help.
1 04 - Again, personally I would put a few more highlights in the decoration here.
1 05 - See 1 04. You make good looking levels, but they all could use a bit more detail in their decoration. Maybe a few spikes from the ceiling, a few extra pillars...etc
This is also a bit of personal preference though.
2 01 - Very nice level, but it's actually harder than it looks. I spend more time on this than a few of the "Hard" levels.
2 02 - I remember doing something similar in one of your earlier packs. Here my main point would be again that it looks kinda boring and bare.
2 03 - This one looks much better though!
Also, the solution is very nice!
2 04 - Personally I am not the biggest fan of levels where it's just the one timing thing and that's it. Again it looks quite bare.
2 05 - This was quite easy for its position. the solution is good though!
Again it could use a bit more in the looks department.
3 01 - This was quite a tough nut. Although the skills kinda spoil you that up is the only direction at the start.
3 02 - The level is way easier than the last one or Normal 1. The solution is nice though.
3 03 - Again, the set-up of the level give the solution away quite easily. It's a good solution, but the only tricky thing is to get the timing on the bashers right. Again a bit more detail in the decoration could be good.
3 04 - The hardest, but also best level of the pack.
I think that your "pillar" themed level look better than the rest as well.
3 05 - Yeah, your intended solution is a bit ambicious at the start and there are too many more effective alternatives. It's still a good level though. I am not the greatest fan of the random lemmings on the map though as they obscure the lem count in comparison to the save requirement. Again, decoration!