Hey, so I played your game, and it is superb! I absolutely love the concept. You see, I've done something very similar to this in a game called LBP2. What I would do is create mechs (ships) and battle. Little Big Planet is a creative sandbox type game, with three main games in the franchise (LBP1, LBP2, and LBP3) available for the PS3 and PS4.
Since I have extensive knowledge on mech battling, and I spent 2 or 3 hours in the ship editor, I'll give you some suggestions.
-I would definitely add the ability for the player to bind keys to directional movement. For example, the left key would move the player left, regardless of which direction the ship is facing. Also, I would add gyroscopic turning. Basically have the front of a ship face the mouse. These could all be "Setting" or "Chips" added to a mech, since rocket movement is a bit primitive. An entire chip system, with upgrades and certain attributes would be nice. I know while mech battling on lbp2, we all started with primitive rocket movement. However, as we grew, we eventually used movements that were precise and instantaneous. There is a chip that effects anti-gravity and dampening. When dampening is set to 100%, the mech wont move at all, not even when something hits it, it's basically suspended in space. Some of these settings could actually be toggled by a player in real time, like the dampening effect. Dampening would also come in handy when a mech has stopped moving, because then it wouldn't continue to float or rotate.
-In the same way that ships can be saved, maybe a way of creating and saving projectiles. These projectiles could then be emitted (shot out of an emitter or cannon).
-Add maybe some binding pieces, like chains or pistons. And maybe even some armor, something that doesn't have a force field like the shields, but just takes some of the damage received.
-Another thing I would add is breakable pieces. Once a piece has sustained enough damage, or undergone enough friction, it would simply break.
-Explosives would both add to frictional damage, as well as physical damage. Projectiles could range from sticky bombs, to hologram beams and hologram bombs. Lazers, nano storms, plasma, fire, etc. The possibilities would be endless.
-I wasn't a huge fan of the energy system, it seems a bit complex from the onset, even though I got a hang of it. I might be a bit biased in that regard, but an easy way to mend that and the lag would be to have a heat gauge on a ship instead. For example, rockets, cannons, and shields would all produce heat, and when that heat is simultaneously exceeded, the mech would reduce the functionality of all active elements until it has cooled. This would allow the player to blaze the cannons, or crank the shields in a pinch. It would also allow flexibility to players who like to stock up on weapons, or spread them out. The heat gauge would build slowly over time from the use of a single cannon, but it would instantly fill and then unfill from a barge of many cannons (kind of like the difference between a shotgun and a machine gun). If you decide to keep the energy mechanic, you could even build on this by allowing the power of each cannon shot to be determined by how much power is being supplied to the cell.
I know that's a lot of information and ideas, and I understand that it's indefeasible to add all of those. My non-mech battle related suggestions would be:
-To simplify the creation process (it can at least be made easier and more intuitive, yet enjoy the luxury of that wide range of customization).
-Some objects can be glitched slightly inside one another while placing them.
-The angle of horizontal and vertical mirrored objects can get un-even.
-Have players even build parts themselves, save and load parts. The player could then load that object while working on his/her ship, or delete it.
-I think that objects should be bound individually, instead of having those 9 nodes. It's complicated working with those, and especially a strain on the fingers if you are spending hours at a time working on a ship.
-Pieces should definitely be drag-able while working on them. To have the ability to drag, delete, copy, stamp (that means place multiple of) and flip would be very nice. LBP solved the issue of pasting objects together as well, you may conciser having a paste feature, or pistons/chains/bolts/etc.
I think this is a great alpha with a lot of potential to be a great game. It reminds me of LBP2 mixed with kingdom hearts gummie ship editor. Keep up the great work man, I hope it gets the attention it deserves.