Below there is a summary of selected extra activities in Uptown, specifically those, which may prove a bit problematic.
1) Mobile Command Centers - Uptown district is the only one where there are two mobile command centers. Moreover, there are three Jammers around here and just as in case of other districts it is good to destroy them from a distance. Getting closer to a mobile command center will certainly draw attention of enemy forces. Unfortunately, you need to remember that in both cases a combat helicopter, among other things, will head your way. Remember to use powerful ranged attack (R1 button) to fire missiles at helicopters, while avoiding their rocket fire at the same time.
In addition to the helicopter, you must also be careful of, among others, heavily armored opponents, who have some other special abilities too. As much as it is possible, try to keep the enemies at bay (at close quarters they can quickly inflict heavy damage to Delsin) using strong attacks to gradually reduce their health. It is worth mentioning here that there is a chance of encountering enemy snipers in the area as well as Auto-Turrets - as always it is best to sabotage those.
The two enemy bases have completely different structures from those that you know from other districts in Seattle. Namely, you need to get to the top of a round walker (Light Speed ability ??from Neon category is very helpful here) and start destroying generators mounted in the side supports (such as in the picture above). Once the main core is revealed, jump to the central platform and perform a sabotage in a well-known way.
2) Blast Shards - You are able to reach one of the shards in the Uptown district only after you have made sufficient progress in the storyline, because it is located on a ledge high above, which is inaccessible at first (the drone is at the border between the Uptown and Waterfront districts). The earliest that you can obtain it, is during mission 17a (Expose Augustine) or the 17b main mission (Kill Augustine), i.e. during your path to the top of the D.U.P. skyscraper (the above screenshot). If you have missed this collectible, you can return to the region of the skyscraper, after you complete the game's storyline, and repeat the initial part of the climbing.
3) Hidden Camera - The camera you seek is in the place shown in the above screenshot.
4) Audio Log - Start looking for the audio log in the western part of Uptown district, and it may happen that the marker appears on the world map only when you get close to the area. Once you start searching for the audio log, you need to examine one of the alleys between buildings (picture above).