Alright, I tried this little game.
First thing that strikes me is that the game's controls are unresponsive. It is quite hard to control the avatar correctly which rises the game's difficulty in a bad way. Altho the concept of the helicopter is interesting, the mechanism doesn't feel as smooth as it could be. The player always have to hold down the up (or w) key in order to rise. Also, the shooting mechanism has no variation through what I've played (perhaps it changes in later levels). Also, I felt like the avatar was very hard to control and I died numerous time while trying to move close to powerups and enemies because I couldn't control the avatar like I wanted to.
Regarding difficulty, I feel like the only difficulty of the game is mastering the controls. Once that is done, pretty much every challenges in the game can be beaten. This causes an inverted learning curve (which is bad): the game is very hard to learn and becomes easier with time. Which leads me to the masterhsip of the game...
The game can be summed up in the following sentence: Tap constantly Up (or W key or right-click) while left-clicking continuously. This is pretty bad in terms of variation and masterhsip. The player needs something to learn besides tapping keys and clicking a mouse. You could add weapons or game techniques requiring the player to hold down the click button and release, you could make it that the avatar doesn't drop instantly once you release the up key or sometimes add challenges that needs to be overcomed by actualy moving around the screen.
As for weapons, I found the upgrades rater useless. The missiles, which seems to be seaking, don't seem to seek very well and have a lower accuracy ratio than I have by simply clicking. The laser saber weapon forces me to move close to enemies which bascialy means rising my chances of crashing just to kill an enemy that I could get rid of when shooting. The minigun and the laser have the same advantage (their shots do not "lob" like the basic shots) so they are interesting to own but do not offer much more. The drone and shield weapons are very interesting tho. When you create a weapon for a shooting game (and any games using weapons), first start thinking about their gameplay implications then add a cool design. The laser sword is very interesting in terms of concepts but in the actual game, it is almost useless. You are more likely to loose than to win when using it. When you create close-range combat in long-range game, always give a really good advantage on close-range combat since it's alot more dangerous. Also, try to find different play techniques and design wepaons around those. For instance, a common play technique found in shooters is "spreading": The player will move around the screen, shooting everywhere, spreading its shots everywhere hitting alot of enemies at the same time. Another one is "focused" shooting: the player will focus on one enemy at a time instead. There are many other play techniques but I'll let you find them out by yourself. It's alot more interesting this way
A thing that bothered me alot was the fact that the basic shots were definitively not accurate because of the lob effect. Although I see a good thing in this ( this would work as a motivational element for the player: change your weapon when you can cuz this one sucks) right now, I feel like it's not implemented correctly. Perhaps it's simply because the player's focus is grabbed too much by the flying mechanism. This would need further research.
The enmy designs are a bit too simplistic in my opinion. It would be a good idea to add more variations to your enemies. Double cannons or flying enemies that shoots differently are only two very simple variations of what you already have. Also, the bosses I've seen (1,2 and 3) are almost excatly the same. The 3rd one is a bit more interesting (but it's concept doesn't seem to fit at all with everything we've seen before. A giant bee leader of small ball-like helicopters and spherized cannons? Why? Why weren't there enemies and designs in the level telling me that we're facing some kind of nature-oriented threat?) but the first 2 bosses are exactly the same since they can be destroyed the same way.
The first 3 levels become repetitive simply because they use the same challenges and look exactly the same. A bit of variation on the levels would help alot. You could make one where you travel upward instead of forward for instance. This is just a very obvious way to add a bit of variation, there are many better ways than that to spice things up.
I like how the game can adapt itslef to all kinds of players. The fact that you can use the arrows, the ASDW keys or the mouse to control the flight of the avatar is a very good touch. The grapical representation of the game fits with it's retro theme and chiptune musics.
Right now, I feel like I've seen this game before even tho it's bringing something rather new to the genre (the chopper thing). But even with that element, I'd still play through old games than this one. Overall, the game has something good going on but it wasn't enough for me.
Well, good job. I hope to see further titles of your team.
Later!