Glad you like it overall.
Drops get easier the further you go. Slimes drop the same items as most others, however their drop rate is much lower. So for the same items, stage 1 has a 0.01 drop rate compared to stage 4 with the same items having a 0.11 drop rate.
This way you could get lucky and be slightly overpowered early, or if you're unlucky you'll have a better chance to 'catch up' with items later on. - Hope that makes sense?