I know this is just a taste of the game and not a full representation, so the following might not be relevant.
Right now the RNG is a killer. I've found that unless you have access to a gold deposit you can't win. To the point where if I don't see an island with it at the start of the game, I restart. Artifacts are a must too. The boost to research is pretty much an necessity.

Another gripe is the manual use of weapons. I've found using 4-5 ballistas is a good strategy. However at the moment it's too easy to click the buttons (Repair, inactive etc) Then not be able to shoot. A possible workaround would be to set the turrets to either manual or auto once instead of having to click manual every time.

I would also like the ability to designate food type to golems. too often they eat raw food rather than meals with boosts.

I think it might be a good idea to make souls a type of currency. The more you kill the more you get. They could then be used in various ways, such as:
1) Upgrade current golems. Sometimes you might be struggling with food and not want to spawn any extra mouths to feed.
2) Some sort of ground scanner tech that would use souls as a one time resource to reveal a part of the underground area.
3) Upgrade current weapons. Maybe something like Beast = faster fire rate, mech more damage, etc.
4) Increase the amount of buildable sapling area. (I know this would need to be balanced so as not to interfere with map gen too much).
5) Upgrade / repair the core.

Very much looking forward to the full release.