Well, I picked this game up on a whim, mostly because of the Steam Sale. I had seen your game previously, but I found your trailers and screenshots unconvincing. I couldn't grasp the thought of this really being a game for me.
But, that was then. This is now.
Now, I see things a little differently. Judging a book by its cover, in the case of GoI, will cause many people to overlook what the game offers. It's not hard to imagine why people would pass this game by, because it's only after you give it a chance to grow on you that the amount of potential fun to be had becomes apparent. What I'm finding to be the appeal of the game can't be capture in a screenshot. The game looks rather plain, thematically interesting, but physically plain in ways.
But that is ok. I am slowly learning that the more I play, the more it has it where it counts.
First Impressions.
I think first impressions are important, especially in situations where the player isn't convinced that this is the game for them. GoI is a bit slow to reveal itself. I find there to be nuances to the gameplay that take time to discover naturally if some thing doesn't point them out. This can make things a bit intimidating or even frustrating at first. So, in my opinion, it's really critical that the game play experience starts off on the right foot for the player. Otherwise, the player may misunderstand the point of the game and quit before the game has a chance to reveal it's value.
So, here are my impression of the game as a player who is/was discovering the play experience of Gun of Icarus Online.
Tutorial
The first thing I did when starting up the game for the first time was to select the tutorial. After completing all 3, I have to say I still had no idea of what to expect during regular play. I felt that they were rather deficient and were too short. Some of the critical things I learned later through playing the game or reading the form, stuff that greatly enhanced my ability to enjoy the game, I feel were things that should have, but were absent from the basic tutorial. Certainly, whatever lessons were to be learned in the tutorial went clear over my head without the context of actual gameplay to help me assimilate them. So really... I think I learned more about the game from actually playing it, followed by reading the forum and wiki outside of the game, then from participating in the 3 tutorials.
Character Menu
I was mostly able to find my way around the menu's and figure out things out through exploration, trial and error. The one thing that kept/keeps getting me is my character select screen. It took many games to understand that if I (unassumingly) don't click the "complete customization" button, whatever changes I've made to my configuration will not stick. Many games have started out, first in confusion and then in frustration when I begin without tools I thought I had selected as a loadout. So, when wanting to try the Buffing Hammer.... I still start with a Spanner. This I chalk up to a basic design choice and differing processes of intent. For example, I select the Buffing hammer to replace the mallet in my loadout screen, assuming that the change is set and then close the character menu without clicking the "complete customization" button. When I join the game, I am without the Buffing hammer and now I'm stuck in game the without my desired tools.
What is this?
"What is this?" is a question I was asking myself constantly. Although the frequency is diminishing, I have a simple suggestion that could help solve it for future new players. There are a lot of things that, once in the game, are not clearly defined if the player has a question about them. Such as Ammo Types, Guns and Tool abilities. Many times I've wondered what name or type of gun am I using... or what does a skill specifically do. But all I have is a un-descriptive Icon in the HUD... and that's not very helpful if I can't remember what the wiki said about it. So why not simply have a small HUD element on the edge of the screen that has the name of the Gun, an icon for it's damage type along with a shorthand and abbreviated description of what buff/nerfs are being applied from tool skills?
What color is what?
As someone who is partially color blind, I have to admit that I have encountered frequent situations where I've not been able to distinguish between ships on blue and red teams. Through a combination of a faded/blended colors, the subdued earth-tone color pallet, rendering ships in the distance and through the environment of dust, fog and clouds... I have not been able to tell the difference between ships on different teams. Combine this with an embarrassing tendency to forget which team I'm on... forcing me to search for some sign of what color my own ship is... with the hud not making it plainly obvious... well, I'm sorry if I just unloaded a volley of rockets on you if you were not actually the enemy.
Beginner only games
Finally, I would like to end this with a comment on Beginner only games. This goes back to the importance of first impressions. Again, my opinion so far of GoIO is that it is a game that must be given some time to grown on you. As a new player, who lacks an understanding of how the game is supposed to look when everything is working as intended, being thrown into matches with other players equally inept at the game will only lead to situations that will foster a bad impression of how the game is fun. For me, in the few games I've played so far, I have played games that were very encouraging and games that were the opposite. Of the positive examples, it was usually because of the quality of players in the game being higher and more experienced. Rather then having games filled equal measures of incompetence. When you are in a game with players "who get it", you are more likely to learn by example and experience levels of progress which lead to fun. When you start off playing the game in which your ship is destroyed more by the environment then by other players ... you're more likely to just quit the game altogether and not bother. You should find another way of providing the means of growing into the game for new players. It is far better to learn by example along side experienced players, then through trial by fire and experimentation along side equally oblivious players.