I really like the graphics style - it reminds me of how we thought in the 90ties how VR would look like. Great! In terms of gameplay I miss the feeling of progress, the power-ups have no directly visible effect and I cannot see how many gems I collected until I die. Maybe adding a gem-counter and making the power-ups visible in some way could greatly improve that.

That game would be give a lot more fun  with sound. You need to add at least sound when player shoot. Also I would recommend to indicate when enemy is hurt bc, as for me, I didn't understand when I hit it and thought that there is something with collisions.

I think map's size is ok for now but as an Ultrakill player I prefer having walls :D

Yeah, power ups are cool

I absolutely love Devil Daggers so I was excited to try this one! The gameplay is definitely solid, the powerups were a great addition to it I would highly recommend giving that part of the game extra time. I don't think the map was too small, but I was having trouble staying on it because of the lack of audio/visual feedback I think. Maybe add some footstep sounds, and have a different floor material on the edges so it makes a slightly different sound while walking there. I also wished the jump had a little more 'oomph', I was having trouble even telling if I was jumping most of the time. I also had the 'quit' bug when I fell off the map, it would bring me to a black room with a single enemy spawner in it, I had to just hit X on the window to close it.

As others have said you the visuals have a really good style, keep building and polishing that and you will have a really great looking game on your hands! Audio would also be a huge help, even just some basic placeholder stuff would help with getting feedback. I hope you keep working on it, with a bit more polish this could be an awesome game!

Also I appreciated how detailed your dev log was, I need to up my game on specific patch notes!

You have something with the visual. It maybe needs a little more polish (not sure how), but it has the potential to look really amazing I think. I really had fun playing the game. Maybe a crosshair to indicate where I am aiming and a hit indicator giving visual feedback of when an enemy is hit would be nice to have. For this the map size seemed fine, but I didn't realize that the edge of the map had drop initially, so I kept falling down. Maybe the white small wall around the edges could be a little different color to make it obvious that there is a fall. The powerups definitely add a lot. All in all great job, need some audio and some more polishing and this will be a great game. 

The sci-fi visual design is eye-catching, which reminds me of Virtual On and Neon Genesis Evangelion. The shooting and movement is smooth, and the weapon upgrade also makes me want to keep playing. Overall, it is fun and has great potential.

Some suggestions:

• Often play halfway and suddenly get hit by the enemy or fall to the edge and game over, it would be better if there are visual cues on the screen or use a minimap to show the surrounding environment when close to the enemy or the edge.
• The UI can be polished and improved more. Especially in the score display, game menu and the interface for choosing upgrades, some more visual design and presentation can be added.
• It’s a pity that there is no audio, the fit BGM and sound effects will bring a completely different level of gaming experience.

Bugs:

• When click quit button, it bring me to an error state which is in a black room and cannot move around. I need to pause and choose quit again to back to game menu.
• The Linux version is broken. It shows "Error: Couldn't load project data at path ".". Is the .pck file missing?".

Great game, had a lot of fun playing it!
The gameplay is great,and very satisfying.
Feedback:

-You did mention that you have not included any sounds, if you are planing on improving this game you should totaly add some sounds when hitting an enemy this would make this game even more satisfying.

-Make it more aparent that you have to hit the blue gems in some of the enemys, took me a while to figure that out you could for example add some red outline with a shader to gems that where not collected(e.g. are in an enemy)

-The map size is fine, but you should maybe add some feedback for the player so he knows that he is reaching the map limit

-Enemy variety, this is something you probably are/plan to work on, if not, some more enemys especialy in the late game would be great.

-The powerups are good, they feel very rewarding.

-Make the time slowdown when hitting an enemy slow down less and  shorter, for me the slowdown felt too much like an fps drop beforre i got used to it.

-And finaly, enemy spawning, I got to about 45 gems, and at this point the enemys were very fast, almost impossible to dodge(that's a skill issue on my side tbh)  but maybe change the spawning system to spawn enemys based on gem count, this would allow you to balance the enemy damage/speed/spawn rate with the players estimated power.

That's a lot of feedback, but don't get me wrong I realy enjoyed your game, those are all things I noticed that could be improved.