The main problem with FSZ lies in its weird texturing that doesn't stick to theme. The zone doesn't feel like a mine, but like something really weird. The gameplay is quite good actually, but the minecart ride (the fake one) should be more complex. The later rooms in Act 2 (we didn't get to play that in the netgame, so I haven't told you much about it) are too repetitive. Look at the room directly before the exit, for example: None of that is new, and it's very tedious and cheap. Since Act 2 is considerably longer than Act 1, you could probably cut that room without replacement.
A problem in LGZ2 is that big circular shaft where the chance room is located. That whole area is too cramped, so you should probably resize it. Otherwise, try to modify the ERZ-copypasta parts even further (especially that laser room). I understand that it's very hard to add something to that zone, since it's already full with gimmicks, but luckily it stands quite well as linear as it currently is. The shrinking gimmick part should be remade though, it's confusingly maze-y and button-reliant, and the shrinking does not actually take any effect since you don't challenge the player gameplay-wise while shrunk. Geez, I regret skipping that zone in the netgame.
