Something so simple it could have been the result of a game-making tutorial, popped onto Steam without even any in-game instructions, but with Steam Card already bolted on? And hosting a multi-thousand key giveaway to boot?
All of this fits perfectly into the pattern of the common Steam Market exploitation scheme.

https://youtu.be/SA9dDk2Ld3o
+ The gameplay mechanics are interesting. You jump from asteroid to asteroid, and each time you land the gravity adjusts itself making the player have to reorient themselves. The goal is to find parts and get to the spaceship before you run out of oxygen.
+ Visually the space themed skyboxes look great
+ Nice soundtrack

- Since the center of gravity changes each time you jump to a new asteroid, you are constantly flipping around which can be a bit disorientating which some may find annoying.
- The gameplay is very repetitive, and there really isn't enough mechanics to keep the game interesting for very long. Each level gets slightly more challenging by adding a few more asteroids, or a few more parts to collect, but you are basically doing the same thing over and over.

Very simplistic game with no depth to it whatsoever.
The idea is fun and intesting for about 10 minutes at which point you have seen enough of it, learned how it works and are waltzing through the levels with ease.
It's one of these "run to the goal before time runs out" kinda games in which you jump from asteroid to asteroid in search of your ship's missing parts to leave the level before your oxygen runs out. That's it. There is nothing else to it.
While this may be fine for people who look for a way to burn a bit of time every now and then, players who look for a challenge will find themselves to be disappointed. There is nothing new to see in this game you didn't already see during the first 5 minutes of gameplay. In other words, unless you like the core gameplay of this game A LOT, it will get boring REALLY fast.

I got this though a 75% discount after crafting a badge, but i still would not recommend it

The biggest issue first:
- The mouse is NOT locked to the game window, so if you need to look around (which you 100% will considering you are constantly spinning around due to the changing gravity) you WILL click out of the game at some point

Other issues:
- The speed at which you turn seems to be tied to the FPS, which is pretty dang annoying even with the ability to mess with mouse sensitivity
- The fact that you need to HOLD the spacebar instead of clicking it is never explained, and the game just refers to it as "jumping"
- The gameplay is very repetitive, different items will always be 'touch it to collect' and that's it
- The UI is weirdly disorienting, because it has a huge windup and follow-through for the slide with every single click
- Levels are separated in letters and numbers (i.e. A1, A2), but there are so few levels per world (just 6) that it becomes credibly annoying to menu through the levels

Only thing i will give it is that the music is good, and the low poly models are cute, but that's it

I didn't like this concept of beat-the-timer jumping on asteroids - successful in case your mouse-aim was right on target at the moment you pushed Space, or not if you miss & just fall back on the previous one. This model doesn't seem to make natural sense to me, is it enough to stare at something to make a 100m salto-jumps in vacuum? Probably the game simulates the last minute of a poor spaceman whose helmet has just experienced seal failure & the oxygen level drops very fast, while his spaceship is always at the farther asteroid. The 'soapy' Unity-engine visuals don't add any appeal to the action as well. Dull menus, no tutorial & such as the dressing.

It's bad, unlike Fallout 4 which is good.

Though a good idea in general, there are better, though more expensive alternatives of the same idea and mechanics.
The best that this one might do is give you motion sickness. Despite fun to run around and collect the things the challenge with the jumping goes to "point at the right direction". Maybe I didn't get to a level high enough for more complexity but what I had was enough.
Now I am going to throw up a few times because of how my senses work, as it was the first time I got motion sickness from something. Thank you, devs ! I might have not experienced it otherwise.

this game, without exaggeration, has the WORST controls out of any game i have ever played, it takes skill to make something that plays this bad, very fun to speedrun though

Felix Jumpman has no real story, so I will be ‘jumping’ right to the main goal. As stated on the game’s description – you are tasked jump between asteroids and collect all air tanks. This is indicated by the coloured arrows and dotted squares shown on your screen. This must also be done before your oxygen bar runs out, or it will be game over.

As for the controls, this is a game that has movements and jumping. Lots and lots of jumping. In fact, you had better be skilled at making leaps if you want to progress anywhere in the game. The angle of your POV plays a big asset in how far you jump, so for beginners it may be confusing at times. The farther the asteroid, the more upwards your vision needs to be when you make the leap.

The asteroids and items are pretty basic to its design, with flat texture and shading. This isn’t too surprising to find in an Indie game, but it could have been better developed. The asteroids doesn’t fit in with how well the background was designed either. Gradient colours of blue, littered with stars made for a stunning BG imo, and really does convince the player that they are in space.

The atmospheric music also added to this. It was calming and rhythmic. The sound effects, not so much. A click sound is triggered whenever the character jumps. This can become irritating when it is running repetitively over a course of time, and I only wish there was a mute option implemented for this sound.

In conclusion, Felix Jumpman makes for an interesting concept: it did not execute the idea well with a lackluster story and character though. I had a light hearted gaming experience, provided with the serene environment and wonderful music. More detail on the character and asteroids would complete the stunning visuals.

Other than that, my interest had vanished after 1/2 hour of playing, and I simply played just to grab all the trading cards.

The idea behind the game is kinda interesting (you jump around comets in space collecting parts of your space shuttle) but the execution is absolutely horrible. My biggest gripe with it is that the camera movement is not 360° with the mouse, making it extremely hard to orient yourself sometimes.

Works fine on Linux with Proton (Proton 4.2-1).