I'm an Amazon Tablet user, having purchased the game from the Play Store and it's my number 1 goto game on the device. Currently I'm close to completing Normal - not yet tried the harder campaigns and I have all unlockables collected.
Some suggestions on where I'd appreciate changes..
A 5 turret ship, 0 hangars at the 11k mark - there's a gap here. You can get a decent 4 turret + 1 hanger ship for 7200, and around 11k you have multi hangar ships but nothing for the non-hangar based until 15k.
Saving ship designs across playthroughs, so when you select the type of ship you want to build the game provides you a list of buildable blueprints (based on available tech)
More persistent rewards - e.g. either after completing a mission and getting credits, OR based on completing a campaign (with reward amount based on difficulty of the campaign), being able to invest in either upgrades for a tech, or being able to put research points into a tech.
To be clearer here, upgrades in a tech
- Having points allocated such that when you start a mission you already have upgrades paid for in a particular tech (e.g. range for the laser point defense). Upgrades available for all technologies that you have unlocked. Perhaps limited so you have to upgrade tier 1 before being allowed to move onto tier 2.
Put research points into a tech
- Spend the rewards on either offsetting the research cost for a tech or being able to full research each. E.g. Invest in Fighter 10% speed so it starts at partially completed and takes less time during a mission to complete.
Edit: Perhaps the persistent reward for upgrades or research could be automatic and based on what you invested most heavily in during the mission or campaign - encouraging players to try out new battle plans.
This would encourage multiple playthroughs to earn the persistent rewards.
For those wanting a challenge, also have in the options a setting for the start level of enemies - e.g. give enemies access to tier 2,3, 4 straight away.
Ideally for a campaign the researching and upgrading would persist and be a lot harder.
So in the first mission I would expect to maybe research 1 or 2 items but when I started the next mission in the campaign I would have access to those 1 or 2 items and be able to keep researching. By the end of the campaign I'd have a lot more options available (ideally not everything, researching should make you focus) but the enemies would also be harder.
Ship based experience - encourage keeping ships alive by having them get experience for kills which increases accuracy, health, shields, range, fire speed, damage. Once a battle was completed, these ships would stay behind to protect the region rather than move on to your next fight and unbalance it.
Heroes - having a single hero that you can level up during a campaign and assign to a station or ship to give it a small boost. When the ship dies the hero escapes in an unkillable pod but loses confidence (experience).
Just some thoughts! Really looking forward to Space Haven, Rimworld is my current favourite PC game and many of the other games that form the Space Haven ideas have been on my regular play list (Loved DF-9 even though it wasn't finished).