Reassembly is clearly inspired by Captain Forever, the art style screams homage. Galaxial isn't even a spaceship construction game though. It's totally different to Istrolid, but yes the art style is quite similar: This is just an easy, colourful, minimilist design style inspired by vector art. We deliberately AVOIDED doing the black with colored outlines thing that Battleships Forever, Captain Forever, Reassembly and so many games in this genre do (And we realized there are a lot). There are actually much better games to look to that are similar to Istrolid gameplay wise, there are MANY in this space but mostly obscure abandoned indie titles. Anyone on the Zero-K forums knows that custom units in an RTS has been a bandied about topic for a long time, and we did it a while ago with custom commanders, but that was never a core of the game. Treeform and I definitely played and talked about Captain Forever, which is a shooter (And another browser game with minimilist, though very different, graphics). When we were looking to 'launch' we did our research though, and came up with this:
Battleships Forever - Seems to be the grandaddy of them all: A freeware strategy game with ship design. Won awards, got a fair amount of attention: Notice it is 'still beta' and talks about the full game. It's been like this for 7 years. This is probably most directly the gap we are filling: The promise this game offered.
Captain Forever - Did actually inspire some of our spaceship building ideas, but is actually itself obviously an arcade shooter homage to Battleships Forever.
Gratuitous Space Battles - Similiar, but all AI vs AI. Not a huge amount of real strategy or balance. Just build a crazy ship or fleet. Less blocky than us.
Gimbal - Arcadey shooter which is entirely online multiplayer, not a very active community. You have to purchase the full game to unlock everything, which feels kind of pay-to-win.
Kerbal Space Program - Very different obviously but there is some appeal overlap and Tree and I definitely both love this game.
Others include: Starwright, Blockade Runner, Battle Fleet Engineer, Block Ship Wars, Fragmentum.
Then there are the minecraft-type ship builders: StarMade, Robocraft, RawBots, Space Engineers.
We didn't realise going into this it would be such a populated genre. I guess it's pretty hard these days to do an idea that's not already been done. But that's okay, Zero-K is just OTA + 19 years, and it's awesome.