Given that it was aimed more at new players than existing ones (and so is more of a detour than a continuation), I think TImelines works about as well as it was going to.
The missions are nothing to write home about (timed EVAs and races, timed mining, repairs, lots of pew-pew); but neither are they long and the bar for earning sandbox rewards is very low (you just need to score 1 star outta 5). The plot is decent, giving off slight Matrix/GANTZ vibes, and the writing is solid (though the VOs are of varying quality).
All in all, it's more stuff to do. It's decent, it won't take long and it'll earn your sandbox save 11 new ships, 7 new systems and a new station or two. At the very least, it'll give Egosoft the money to keep improving a six-year-old game, which -- in my book -- is a fair trade for 15 bucks.
EgoSoft has provided GOG the Linux version, but as per always, the offline "backup" installers are second class on GOG, doubly so if they're Linux. Linux users have to fanangle the windows version installer to get the DLC to actually play on Linux, despite the game performing better on linux and the company making the game officially supporting Linux.
Now, the DLC has a difficulty curve. It's not for sandbox, but i don't know why you bought it if you didn't know that, so it's not fair to review it on those grounds. It is certainly an advanced tutorial, or teaching through hard knocks. Those who played Monster Hunter will understand what i mean by Arena Quests. This is what that is: instead of bringing your own stuff to the missions, all equipment is provided for you, which means if you're used to coming in stronger than absolutely necessary, then you're gonna get wiped. That said, the actual threshold for both clearing and unlocking is way, way easier than you'd think. The first mission is a race, and I ran through it and kept quitting and restarting every time i'd miss one of the hoops, because in most games that's a problem. I decided to take EgoSoft's advice and accept my fate going through: yes, i missed the goals many, many times, but simply finishing the race will net you 1 star. I got 3 stars.... constantly missing and having to turn around. Second mission seemed impossibly hard, but, frankly, i know it's because i'm doing something wrong. Your approach matters, and they don't seem to give you enough ideas on what that approach would be (but, hey, this game is about thinking for yourself, but it's still framed as lessons so they should probably figure out what they want to do).
4☆ material if GOG can get their act in gear.
This DLC is different from all previous ones.
The previous ones expanded the sandbox universe and added a few missions to the added sectors/species.
This DLC, on the other hand, takes place mainly outside the open X universe.
The focus is on encapsulated missions, which on the one hand are (mostly) well constructed, and at the same time use possibilities that would not have been feasible as missions in the open universe.
The missions shed light on many areas of the game mechanics. From space battles large and small, which require special tactics. Simple trading tasks. But also unusual scenarios such as races, defusing mines, repairing stations and much more. There are also some special missions in which you play historical scenarios from the predecessors and take on a different perspective.
There is also a storyline in which the player has to solve a mystery.
In addition to these missions, the DLC also introduces several other sectors and hidden spaceships into the open game universe. These can be unlocked through the missions and you will receive rough information on where to find them.
