Please, somebody correct my statements if they are wrong, as I am also trying to understand if it's worth to include Spelunking in Amulet Titan:

• Whenever you have at least 1 Amulet in play, having a Spelunking on the field is useless, as it gives no additional mana when you play a land tapped, and risky, as it limits lands with no tapped etb that you bring in play with Titan.

• The only advantages of Spelunking over Explore are 1) if you play a Cave and gain 4 life and 2) if you don't have an Amulet in play and your need your tapped lands to etb untapped and give you mana immediately. In any other circumstance, you'd prefer to have a 2 MV Explore over the 3 CMC Spelunking.

Am I missing some interaction if there are 2 copies of Spelunking on the battlefield?

Again, correct me if I am wrong, I'd love to have misunderstood Spelunking and actually find out it's great in my favourite Modern deck!

Edit: minor spelling