I'd say it's different rather than better. There is some continuity but enough is explained that you can probably play it without the original. The second game is larger and more open but not always in a good way (spending minutes walking between puzzles to the point TTP2 now gives you an Oblivion / Skyrim style compass and quest marker just to find the puzzle entrances in a mostly empty world starts to wear a bit thin halfway through). There's more "social interaction" with peers but I'm not alone in finding it way overdone and out of balance. The original was a quiet reflective game with occasional musings of regret from a melancholic God that involved uncovering the plot yourself via audio logs and terminals that gave you time to reflect. The whole of the TTP2 outside the intro now involves one giant game-long escort quest completing each of the 4x worlds whilst babysitting 3-4 peers who just won't stop talking both over the radio and sending messages even in the middle of trying to solve puzzles. The "subtle" relaxing / philosophical / meditative feel of the first game is definitely gone and replaced with just being bombarded with over-stimulating chatter, and the in-game "social media messaging" definitely wasn't as cleverly done as the BBS system in Road to Gehenna.

Finally, they dumped their superbly well optimised Serious 4 engine in the original for stutter-fest Unreal 5, so expect a lot lower performance on same hardware (as in the same hardware that got +120fps On Ultra in TTP1 will get frame-rate drops down to 30-40fps even on Low in TTP2, it literally runs 5-8x slower) on top of the usual Unreal 4-5 annoyances (TAA bluriness and that God-awful 'Auto Exposure' / Eye Adaptation effect forced on in so many UE4-5 games with no way of disabling). Overall, TTP2 isn't a bad game but between the two I very definitely preferred the original by a very large margin.