most of them I understand multiple and gold but that's it level, magnet and rank not too sure. Emerald and sapphire I don't see a difference them the last one No idea what so ever
Rank gives a multiplier to the amount of gold you receive from your tower based on it's level. Level tower multiplies the amount of exp you receive for each block that falls that increases the Rank bar. Magnet is a currency used to purchase upgrades and the Magnet Tower multiplies the amount you receive when they're unlocked. Similarly Sapphire and Emerald have their own prestige upgrades that you sink that currency in to.
Yeah level tower seems to be broken but everything else beyond seems to be functioning at the least or the incremental is so low that it's negligible of a bonus. Aside from the level tower I was explaining the functions of the others to the previous comment and sadly the game is abandoned so I doubt level tower will be fixed.
Noted. I'm not sure either, as it's the next thing I unlock
Update: I've unlocked it. I'm not quite sure what it does still, but when it gets to a new highest rank, my money increases by quite a bit.
Update 2: Once level tower hits 9, you get a huge increase in monetary gains. So it probably is such a minute amount of bonus until it gets to higher levels