Utopia Must Fall from developer Pixeljam has absolutely absorbed my attention recently. It's easily one of the best modern arcade shoot 'em ups I've ever played. Note: personal purchase.
It's like a glorious mixture of Missile Command for your base to defend, with Space Invaders for some of the style and enemy behaviours along with a seriously mysterious moody atmosphere, one that really sucks you right in. So it's a mixture of classic retro arcade gameplay with some tower defence. Add to that the rapid constant progression with you upgrading constantly, there's a lot to love about this.
Spread across a few differently styled cities, you're tasked with one single objective — defend against the apocalypse. You do so by swinging a great big rail-gun that auto-fires. Its position is static, so all you do is swing left to right to align it as it fires as you try to take down every single enemy that appears on screen.
The tricky bit is how your main weapon is a bit slow to align, although there are upgrades to speed up its rotation. The upgrade system is what's the shiny hook here. You choose your own path through it. After each day, you're able to pick certain contracts to power up something. This could be upgrading nuclear missiles with antimatter that end up sucking everything in, automated facilities to send out configurable drones to help you defend, increase gun fire rate (or twin guns) and so on.
You can re-roll some upgrades you get if you don't like them, which is done quite amusingly in-world, in the way of a Citizen Proposal. This might be something like constructing a decoy city, or invite the aliens for a chat. They don't do anything, other than let you re-roll upgrades but a fun touch.
On May 14th, they just launched a big update for the game including:
- Skill tree: fully overhauled upgrade system with interactive tree structure, graphical icons for every upgrade and 4 special 'opportunity' slots. Requirements, blockers, hierarchy and time constraints for regular upgrades are demystified.
- Drones! Automated floating, modifiable allies that dodge hazards and chase enemies, equipped with onboard railgun turrets and adjustable behavioural parameters.
- Drone-related upgrades: Deploy Drone Factory, Twin Drone Factory, Atomic Drones, Double-Barrelled Drones, Robotics Specialist
- Watchtower mod: Q Disruptor - targets are temporarily timewarped to 0.25x regular speed
- Opportunity Upgrades: Cheap Nukes, Work Retreat, Red Flag Day, Context Switch
- New cities to defend: Cairo Horizon and HyperParis
- Many other additions, improvements, tweaks, balances, fixes, etc.

Direct Link
It works well on Desktop Linux with Proton, although the Steam Overlay didn't seem to work for me. On Steam Deck, they're working on support but it's not yet ready. They didn't seem particularly happy last year that Valve already gave it a Playable rating.
Cheap too, with a 30% discount until May 28th and even when not discounted it's very reasonably priced. They even note this as a feature: "reasonably priced to help offset the unreasonable cost of everything else".
I just can't get over the atmosphere of it. Brilliant.
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