I usually don't post here that much about my indie homebrewing as much as I do on other platforms because this is a pretty dang OSR forum and I'm...not an OSR player. But I do have a game I'm working on.
Selection: Roleplay Evolved is a hard science fiction strategy RPG. Unlike other strategy/ tactics RPGs, Selection is designed for theater of the mind gameplay rather than miniatures.
Before the game begins, two survivors of the Protomir Civil War teleport to earth and make themselves human with the fragments of the technology left in their pockets. One is the Arsill, who will gather the party together, tell them about what's happening, and offer the PCs information and alien abilities in exchange for help. The other is the Nexill, the campaign's de facto antagonist. The Nexill only wants revenge on the Arsill, and is willing to make Earth uninhabitable just to ensure the Arsill cannot hide here, but will also actively pursue and grief the party as a way to get at the Arsill.
Mechanically, Selection runs a completely custom dice pool system where you roll a pool of four mixed step dice and count dice showing 3 or less as a success. You usually also get a reroll round where you reroll some or all of those four dice. Selection's core mechanic has almost zero arithmetic, but is exceedingly feature dense and basically requires an experienced roleplayer.
The initiative system is a LIFO stack mechanic reminiscent of the Magic: The Gathering stack. Once per round you get an AP recharge (5 AP by default) which you must budget to last the entire round. When a player declares an action, it forms a Queue. Another player may declare an action in response, cutting in line to get ahead of the first action. An example of this in action is the Damage Intercept spell, which replaces healing spells. Damage Intercepts create a damage nullifying aura which only last the instant an attack connects and must be declared in response to an attack.