This was the first Trials game I ever played, and it's great. Don't let the negative reviews put you off, most of them are negative simply because it uses Uplay, which I shall talk about further down the review.
First off, the environment in this game is stunning. For a game like Trials, in which you just ride your bike across level after level, you wouldn't expect this level of quality, the world looks like it's part of a much larger game. There's also plenty of variety, as you quickly move from the futuristic city to platforms in the sky, ancient ruins, outdoor courses, underwater bases and even the planet's core. There is also some slight hints of story included through a few characters talking throughout the game, which hint at how the world became like this.
It's trials. You drive your bike, tilt your weight and try to make it to the end as fast as possible and with as few failures as possible. Every level also has three challenges that encourage you to play differently, and some even involve minigames entirely different to how the game is usually played. The difficulty as you pass through the levels is done very well. By the time I was met with much harder obstacles, I'd already got a basic idea of how to surpass them, and not once did a death feel cheap.
The DLCs add some nice extra content that also gives you a look at more of the world of Fusion, and provide some decent challenge. I wouldn't recommend buying them seperately, but if you don't want to buy the Deluxe Edition, here's a summary of their content and quality: Riders of the Rustlands
The first DLC and the weakest. Featuring only 6 levels, an FMX course and a mediocre minigame. Not really worth £4 compared to the other DLCs, skip this one and get another. Empire of the Sky
Same as above, 6 levels, FMX and a minigame. The levels are a bit better than Rustlands, but still not worth £4. If you've beat the game and want some more fun, get this DLC. Otherwise you can ignore it. Welcome to the Abyss
Breaks the chain and includes 8 levels instead of 6, as well as the FMX and minigame at the end. This DLC gives an interesting look at an underwater empire that used to live under the ocean. Some story is delivered through another AI who speaks to you at certain points. The levels are of a higher standard than the first two DLCs, and I think barely justifies its £4 pricetag. Fire in the deep
9 levels, FMX and a minigame. In this DLC you are even further down, underneath the planet's core. As you move from level to level you go further underground, giving a nice indication of your progress through the DLC. There are also multiple secret recordings hidden around the levels, which give some extra information about the world, and what went on in the mines. Worth it. Fault One Zero
Personally, I believe this is the best DLC. It drops one level and returns to 8 trials again, but the quality of the levels steps up greatly. This DLC has a focus on technology, much more so than previously shown, with teleporters, anti gravity machines and Mechs featuring. The levels in this DLC are very inventive, including one that repeatedly glitches between looking normal, and a blue cyberspace-esque environment
and an interesting level in which you drive around inside three arcade machines!
This DLC is definitely worth £4. After the Incident
The sixth and final DLC. Same as above, 8 levels with an FMX and Minigame. One of my main disapointments with Trials Fusion was the lack of detail as to what was happening. I understand that this is a game solely based on a random guy riding a bike through obstacle courses, but with such an interesting world, with many deeper story elements hinted at throughout, I really wanted to learn more. After the Incident does so nicely. It's set in the future, when all the world is in ruins after the aforementioned "Incident". The levels all focus on fairly different areas, all destroyed or going through some form of crisis. Similar to Fire in the Deep, you can find secrets in the levels, which give you some backstory as to how all of this started. The way this is done is great, as SynDI talks to you through a dating game text box, with amusing exagerated changes in her expression as she talks.
If you want to know more about the world behind Fusion, or just want to play even more levels, this DLC is worth the money. Deluxe edition
I'd like to point out that this game has gone on multiple sales, but not a single time have the DLC packs gone on discount themselves, and it doesn't look like they will at any time unfortunately. As such, I highly recommend you get the Deluxe edition during a sale, I managed to pick it up for £10. Otherwise, if you beat the game and decide you want more, you will be paying a much higher price. Say you got the base game on sale for £6. Now if you got three of the DLCs, that'll cost you an extra £12. Half the DLC total DLC and you've spent £18 already. The Deluxe edition is a much better purchase (During a sale of course. The DLC is good but not worth £30!)
Why the negative reviews?
Now, there are three main flaws that have gave this game so many negative reviews. First main point is the multiplayer. I played the game entirely solo and had fun, I can't really comment on it.
Secondly, people seem to be complaining about this being a bad port, and having a many performance issues. For reference, I ran the game on an i5 3570k, 8gb RAM and a GTX 770 with constant 60fps and no issues of any kind. The issue may be related to lower-end machines.
And as for the last point, UPlay. The majority of these reviews are from people starting the game, seeing Uplay, closing it and leaving a bad review. I will say right here that if you avoid this game because of Uplay, you are stupid.
But UPlay sucks!
The impact of UPlay is nowhere near as bad as the reviews make it sound. You start the game on Steam, UPlay appears, takes a couple seconds to log in, then minimizes and starts the game. You only need to interact with it once in order to create an account, and after that you don't need to touch the thing, aside from closing it when you are done.
All in all, I recommend Trials Fusion to anyone who is an existing trials fan, or enjoys 2D games with high difficulty. Though the price is a little steep for the content on offer, so I'd suggest waiting for a sale and getting the deluxe edition. As earlier stated, it's much better value as the DLCs never get discounted, and only costed £4 (the price of a single DLC) more than the normal pack in the latest sale. And finally, do not avoid this game because of UPlay, there is no reason to.