It's a really interesting game with a LOT of potential.Right now I feel there's a slight unbalance with the items, especially since you can use as many as you want during your turn; also, the magnifying glass feels too OP.
May I suggest something? Add GREEN shells to the pool. Reds are live, blues are duds, but greens are either live or dud. That way, if you use the magnifying glass you still have the danger of spotting a green shell, making the item less infallible. Yes, this adds another element of randomness, but perhaps just make the green shells rare.
All in all, a very good game. Keep it up!