Someone should have thought of this long ago...
Brent Spivey (author of the Origins nominated Havoc fantasy skirmish rules) is beta testing OP4S. For $5 you get the final full pdf version when it releases plus 50% off any print copies.
The Game Concept
Units pay for actions with a resource called Command Action Points (CAPs). However, units can "Overdrive" or make extra activations for an escalating cost... I.e. the 2nd action would cost double, the third would cost triple, etc.
The dice rolls favour the buckets of dice approach with opposed rolls which has been popular lately, with 1-3 a fail and 4-6 a success,with defensive successes used to cancel out attacking successes.
OPS4's RTS soul has a lot in common with games like Supreme Commander
The game scales to 2mm, 6mm and 10mm for bigger battles
A Game not a Simulation
Units have ratings for Attack, Defence, CQ Combat, Resilience (Toughness), and attack and movement ranges. They also have specialties and traits that give them unique roles.
Though there are rules for overwatch and suppression fire, the game makes no pretense at hard sci fi and realism. It has more spiritual links with Starcraft, Supreme Commander or C&C Red Alert than it does with games like "Tomorrow's War." Along with ambushes and airborne units, there are RTS-esque features like Propoganda Towers, and armies can have Command Doctrines.
It has a RTS mode where you must build a base and capture objectives which give you resources for movement (CAPs) and building units (Credits). You can upgrade your tech levels, and the aim is to destroy the enemy base...
Defending bases, gathering resources, capturing buildings... sound familiar?
I was expecting "Havoc in Space" but Mr Spivey has impressed me by not using the same game engine as his other games but branching out in a new direction for a different era. Many rules designers get an original, interesting concept (2HW, Ganesha for example) and then repeat it ad nauseum with only slight cosmetic changes for different eras and genres. Even from OP4S's competitors little is new - Tomorrow's War is simply a modern ruleset with a few laser guns and robots bolted on, and Gruntz copies Warmachine mechanisms so thoroughly I'm surprised Privateer Press isn't concerned. This makes OP4S a surprising and welcome breath of fresh air. The "Overdrive" mechanism has many applications and offers many interesting choices. Move one unit repeatedly or many units once? Or a combination? You have to weigh the risk vs reward with each action you spend.
My GZG UNSC will be re-tasked for a new game...
Use what you have...
There will be profiles for minis from GZG, Combat Wombat, Rebel Minis, Micropanzer, and Old Crow among others. Basing can be individual or grouped. 15mm lovers, rejoice!
Verdict: This is only beta, but already looks like a worthy contender alongside Gruntz and Tomorrow's War - fulfilling a different niche and giving more use to that 15mm sci fi goodness!