Shorebreaker

Shorebreaker is a drone-combat roguelite fought above, on, and under a breaking wave. Every day a runaway drone fleet comes for your island; you meet it on the water, salvage what you destroy, and rebuild before dawn.
They used to deliver burritos
Zippity Drones Corporation pivoted to combat drones to please its shareholders, and now, rather predictably, rogue fleets are leveling the Pacific one island at a time. Yours is next.
Earn bullet time and autopilot
Three custom pilotable drones (and constructible beach turrets) answer to you: a surf drone, an aerial combat quadrotor, and a welding drone. Upgrade automation systems, and your drones can fight autonomously when not under your control, but poorly.
So every wave is a question about where you personally need to be. Land a hit, switch drones, land another fast enough, and time slows down. Flow state, not because you pushed a button but because you earned it.

Meet them on the water
You know this bay. You know this wave. And you know drones.
You have a fabrication kit, the drones, a wave energy harvester, and a right-hand reef break. Ride your surf drone down the face. When their drones close on yours, drag them into the impact zone and let a few thousand tons of ocean land on them.
Time it right and you are in the barrel watching it happen. Time it wrong and you go over the falls with the wreckage. Dive under the swell to torpedo any submarine threats. Switch to the aerial and strafe the fleet from above.
Do all of this from your laptop on the beach.

Someone has to hold the camera
The aerial is also your third-person camera. Every camera you play through is a machine you own or your own eyes, so your third-person shot is from the drone flying behind you. And it can be shot down.

The ocean is a weapon
A harvester moored out in the swell banks energy off every wave that rolls past it. Dump that charge into the next wave and it arrives big enough to sink anything you dragged into the break. Be clear of it when it lands, or it sinks you too.
This is the same power grid that runs your camp. Spend it all on the wave and your turrets go dark until it refills. Nothing about that is a menu. It is a bar you can see and a decision you make live, under fire.

Everything here can be destroyed and rebuiltf
Your entire base (3D printer, scrap silo, automation cores, turrets) comes apart under fire and goes back up if you have the scrap. Zippity comes for all of it in order. Then they come for you.

When the last drone goes down, you stand up
Jetpack, wrist laser, shoulder missiles if you found them. You are not the fallback plan. You can break them on the shore.
Hold the printer long enough to reprint a drone and get back in the air or on the water.
Or you can run. Retreating inland saves some of your parts and costs you the camp. The run does not end; you just start tomorrow poorer.

Split screen - fight together or blame your friend
Bring someone in on the same couch, or over Steam's Remote Play Together. Player two picks up any drone and switches freely, so one of you can hold the water while the other works the sky. Either of you can drop into a beach turret instead, and the third drone flies itself if you have the automation parts.

Only player one is the engineer. The laptop, the printer, the camp, and the last stand are theirs. When the drones and turrets are gone, player two has nowhere to be. They wait, hoping (or laughing).

Clean kills earn better loot
Shred a drone with gunfire and you get scrap. Take it down clean with an EMP, an electrical arc, or a wave that drowns it, and you might earn a whole hull with no holes in it. Dive to the seabed and it is yours, parts still attached. 
Mark the part and your welder drone flies out to attach it mid-combat. It can be shot down doing it.
Something is watching how you fight
Every morning the tide leaves parts on the sand, scrap to collect, and telemetry intercepts from Zippity's Hub. It taunts you. Then it makes an offer: a harder fight tomorrow, for better parts?
Why would it offer you anything? Because the better you fight, the more interested it gets. It has never seen a human run three drones so well.
Key features
Fight above, on, and under a breaking wave with water physics.

Your third-person camera is from a drone that can be shot down.

Local split screen co-op.

Three pilotable drones and beach turrets, with bullet time that you earn.

How you kill decides what you loot.

Weld upgrades on under live fire. 

A fully destructible and rebuildable camp.

An enemy brain that watches how you fight, and adapts its waves.

When the last drone goes down, you stand up.

Pailside Games is me. I build Shorebreaker in the evenings after work, in between diaper changes (hence the Pail). So really, thanks for reading this far.