Fizzy Fizze

Do not buy if you already played the original, even then don't buy it. Find a Platinum cartridge on ebay or emulate it. Platinum is a way better version for both Diamond and Pearl. More to do, more pokemon with the addition of the national dex which both D/P don't have, pacing/gameplay is a lot faster, Platinum is honestly the superior gen 4 game. But if you have to play gen 4, the remakes are fine. There are QOL additions, like how HMs are used in the overworld and the reworked Underground, that makes the remake superior to the original. But do not buy the remakes if you already played the original Diamond. There are not enough new things to warrant you to purchase if you played Diamond on the DS.