I came across this on a list of great games from the last year you probably haven't heard of and picked it up
Proviso: It is an early access title I know some people dislike those
anyway the basic idea is simple top down 2d space shooter edges of the screen wrap you have a little ship basic thrust based movement and directional fire not quite twin sticks as you always thrust forward (for the most part some mods alter this) you have weapons shields and ship types you fight of waves of enemies and collect orbs to upgrade
The upgrades are somewhat random
Where it gets interesting is where this randomisation changes the play style. The first thing you get is a weapon type this replaces the default projectile with some specific method of fire and you get a set of random options for what to choose. These weapon types all play differently there is a split shot that fires three projectiles ahead of you, missiles which fires a swarm of seeker missiles (you reload these when not firing or slowly when firing), grenades that fly out and explode, vortex that charges up shoot out a little black hole and then sucks in enemies based on how much you charged (you also take more damage while charging), blast which sends out a wave of damage around your ship in a circular fashion, rail gun a straight long range shot, torrent a forward facing short range energy attack, flack cannon (space shotgun), there may be others I've not unlocked yet,
Each of these plays a bit differently.
After that you get a shield type these are again different AMP amplifies damage under certain conditions, burn is a dot for things in its range, warp teleports you when it fails, reflect bounces off enemy projectiles, time slows enemy projectiles.
Then you get a ship body type upgrade these are things like Assault which boosts attacks, Sentinel which boosts defence, Firefly which makes your ships thruster bigger and do damage to enemies, Spectre which cloaks when still or slow and does more damage from stealth, Engineer which boosts constructs like mines drones allies or turrets, Hull breaker which makes your ship do ramming damage.
So those three starting points make for very different approaches but on top of that you get more upgrades that alter those starting points further.
One of them add drones to your ship and those drones can then be upgraded to have more or have them shoot rockets or increase damage on enemies you are shooting at or act as defence taking enemy bullets or being more offensive actively seeking enemies.
Or you can drop mines then more mines then mines that seek then mines that explode with a greater radius
Or you can increase various effects of your weapons like blast radius of shots or greater spread or number of projectiles or increased radius adding things like dot effects charged shots and so on.
There are also then upgrades to your ships shield increased radius faster recharge and hull upgrades making it stronger or regenerate and so on
Some of the upgrades have tradeoffs so you regenerate your hull fast but you have no shields or you fire constantly but the longer you do it the more damage you will take and so on
Some add changes to the movement options allowing a reverse thrust and then a strafe or increasing your speed or turn rate or changing the damage you do based on speed.
Given these additions are randomized each play through tends to go down quite different paths I had a fleet of drones with a ship that fires short range blasts and the dot shield. I had a very tough ship with the hullbreaker option that does more damage the faster it goes such that you just blast across the screen slamming into everything, I had a split shot with slow shield that I upgraded such that I fired loads of projectiles in 180 degrees and so on
It makes it very replayable and there are further options to unlock with mutators that alter the way the waves work or increases the randomization of the mods and as you do more runs you can unlock more upgrades etc
All these elements combined with a nice neon art style and lots of interesting visually distinct enemies and boss encounter make it quite a fun game to just pick up have a few runs and then put downs.
Anyway if you like this sort of game it is worth checking out