The vast majority of items in Terraria can be used to create other items, often requiring specific crafting stations (which themselves must be crafted). This is the core of character advancement, since gear defines nearly everything about your character.
There is little to show progress in the game other than gaining items and building structures. Progress can seem to take a long time because you have to collect every item needed to craft the necessary tools, equipment, and materials to advance.
Thanks to the roguelite aspects of the game, there is randomly generated levels, which means fresh gameplay each time the game is played. There is also 4 different characters available in the game, each of which has a different boss fight at the end of the game as well as different characteristics...
The game can be difficult, especially when first starting out. This may mean a lot of deaths and a feeling of no progressions due to having to start over a lot. While the game is not unmanageable for players who enjoy the games genres, it may be a bit of a turn off for newcomers.