You have been transformed into The Terrarian, this transformation starts you at a peak human physique of your own design with incredibly potential for growth. You have the ability to craft everything in terraria, both modded and un-modded, regardless if you are able to craft it normally. Although you may require other esoteric materials in place of the ones naturally used in the various recipes, all bosses will have a respective spawner that will be craftible no matter what realm you are in, however that does not equate to them being easy. Bosses will drop loot and material that are both natural to the terraria world, and adapted to the realm you are in at the time of summoning. Everything crafted by you is indestructible and will not lose durability or experience wear and tear as such creations are now subject to Terraria Physics.
You are able craft Life Crystals and Mana Crystals, as that is the only way to find them besides completing achievements from the endless list of Achievements that you have access to you. These achievements can grant you bonuses that scale with difficulty, these bonuses can be anything from increases in damage to specific entities, to materials you require. There is no limit to the number of Life and Mana Crystals that can be earned through achievements, although there is a limit to the number of Life and Mana Crystals that can be used through crafting.
You have access to an Inventory with no weight or quantity limitations, you only have to touch an object to put it in your inventory. No time passes for items in your inventory, they will be in the same condition as they were when stored. You start out with a limit of seven accessory slots, although more can be unlocked via Achievements.