Sonic Mania
I was pretty much a NIntendo household growing up so my nostalgia for Sonic is limited. The few times I played it over friends' houses I remember the large sprites and fast levels a bit offputting as it favors course memorization over reaction. Luckily televisions have evolved into 16:9 and Sonic has aged quite nicely as a result.
Sonic Mania brings back the original environments with new obstacles and the ability to play as different characters. The time trials add pretty much infinite replayablity for gamers across the world to constantly compete for lower times. The bosses are great, the Sonic 3D bonus levels are a nice addition, and they even added a DLC with Mighty and Ray for more stage variants!
The soundtrack contains music from the original series remixed and rearranged by Tee Lopes and a few others. I wish Michael Jackson was alive to appreciate it. I think this is how he would have wanted Sonic the Hedgehog to sound.