Games Like They Are Billions for Colony Defense
Find games like They Are Billions by comparing colony management, fortification, resource pressure, horde survival, and action-heavy defense hybrids.
The right game like They Are Billions depends on which pressure you refuse to lose. Choose Age of Darkness: Final Stand for fantasy horde survival, Diplomacy Is Not an Option for medieval kingdom defense, Border Pioneer for a frontier economy under wave pressure, Cataclismo for castle construction with a Roguelite structure, or The Riftbreaker for direct combat beside an alien base.
These are not interchangeable survival RTS games. Each keeps a different part of the colony-under-siege formula and gives up something elsewhere.
They Are Billions is the benchmark, not another pick
They Are Billions is the reference point: a steampunk Base Defense and RTS hybrid in which zombie waves threaten a colony. Its appeal is the link between preparation and catastrophe. Economic planning, expansion, sealed approaches, and a supported defensive line matter because one neglected route can compromise the settlement.
A suitable alternative has to keep defense central rather than treat an occasional siege as a break from ordinary expansion. The five picks split into distinct defensive models:
- Age of Darkness: Final Stand: Survival RTS and Base Defense against nightmare hordes.
- Diplomacy Is Not an Option: Medieval Base Defense and RTS built around castle defense and kingdom management.
- Border Pioneer: Colony simulation and Base Defense with an economy and wave-based sieges.
- Cataclismo: Castle-building tower defense with horde survival and a Roguelite structure.
- The Riftbreaker: Action-RPG and base-building hybrid with alien wave defense.
That classification matters. A player who enjoyed directing a settlement from above may not welcome The Riftbreaker’s action layer. Someone who wants to physically shape a fortress may accept Cataclismo’s move away from conventional colony management.
What makes an alternative a genuine match
Five criteria carry the decision:
- Positioning: Do routes, defensive coverage, walls, or placement choices materially affect survival?
- Economy: Does growth directly support defense, and does expanding instead of fortifying create risk?
- Escalation: Is pressure delivered through waves, hordes, armies, or another sustained siege system?
- Fortification: Can you prepare a meaningful defensive structure rather than rely entirely on mobile units?
- Recovery and replay: Does failure reveal a readable weakness, and what makes another attempt different?
None of these games answers all five the way They Are Billions does, which is why the picks below are organized by the pressure each one preserves rather than by a single ranking.
Choose Age of Darkness: Final Stand for fantasy horde survival
Age of Darkness: Final Stand makes the clearest thematic shift while keeping the survival premise. It replaces steampunk zombies with fantasy nightmares and frames defense around a final stand at the light.
Best fit: Players whose favorite They Are Billions moments came from watching an overwhelming horde approach a settlement that had to be ready.
Skip if: The colony economy, rather than the last stand itself, was your non-negotiable feature.
Its defensive model is Survival RTS combined with Base Defense, with nightmare hordes as the source of siege pressure. That makes it the Hardcore-leaning horde-defense option here: the threat is mass, and the settlement has to absorb it.
The tradeoff is emphasis. Age of Darkness preserves hostile mass pressure and settlement defense, but its pitch centers on the last stand rather than on whether choosing growth over immediate protection creates the same tension as the benchmark. Choose it for the fantasy horde and last-stand premise, not on the assumption that every part of the They Are Billions economy has a direct equivalent.
Choose Diplomacy Is Not an Option for medieval kingdom defense
Diplomacy Is Not an Option is the stronger conceptual match for players who want defending and governing tied together. Its loop combines medieval castle defense, massive attacking armies, and kingdom management.
Best fit: Players who want to exchange a steampunk colony for a medieval kingdom without abandoning sustained siege pressure.
Skip if: You want a Roguelite run structure or prefer personally fighting at the defensive line.
The model remains a Base Defense and RTS hybrid. Pressure comes from massive armies attacking the castle, while kingdom management supplies the broader strategic layer. That makes it a more relevant alternative than an ordinary medieval RTS where defense appears only in isolated missions.
Pick it because kingdom management and mass-army defense are both central to its identity. Don't pick it expecting its fortification rules or failure model to mirror They Are Billions; the castle and the kingdom, not the colony perimeter, are what it asks you to hold.
Choose Border Pioneer for frontier economics under siege
Border Pioneer has the most explicit connection between colony management, economy, and recurring attack pressure. It combines a colony simulation with Base Defense on a hostile frontier, built around an economy and wave-based sieges.
Best fit: Players who most enjoyed deciding whether a settlement was economically ready for its next defensive test.
Skip if: Elaborate perimeter engineering—walls, route-sealing, chokepoints—matters more to you than the economy.
The wave-based siege structure is a clear escalation system: attacks recur as part of the defensive loop rather than arriving as a vague survival threat. The frontier setting preserves the feeling of building in hostile territory rather than defending a finished fortress.
Border Pioneer’s advantage is that economy is part of the premise, not a backdrop. This is the most promising fit when “colony economy plus wave sieges” is the combination you need.
Choose Cataclismo for construction over colony management
Cataclismo is the construction-led alternative. It combines castle building, tower defense, horde survival, and a Roguelite structure.
Best fit: Players who remember the fortified perimeter more fondly than the settlement economy.
Skip if: Managing a persistent colony is the part of They Are Billions you want to preserve.
The central mechanic is castle construction against hordes, which puts physical fortification more squarely at the center than in any other pick here. The model also moves closer to Hybrid Tower Defense: constructed defenses and horde survival take priority over a conventional survival RTS label.
The Roguelite structure is the decisive change. It gives Cataclismo the clearest replay framework in this group, but it also changes what loss and rebuilding mean. Treat it as a game where fortress construction and repeated runs replace part of the long-form colony appeal, not as a straight reproduction of it.
Choose The Riftbreaker when you want to fight beside the base
The Riftbreaker makes the largest perspective shift. It combines an action-RPG with base building and asks you to defend against alien waves on a hostile planet.
Best fit: Players who want base preparation but don't want to remain only an overhead commander.
Skip if: Direct action would distract from the economic planning and perimeter management you came to preserve.
Alien waves provide the siege pressure, while base building keeps defense central. The action-RPG layer splits your responsibility between constructing the base and personally fighting. That is the feature, not a side detail—and every task placed on your character pulls some attention away from pure strategic direction.
Choose The Riftbreaker if standing near the defensive line improves the formula for you. If the appeal was planning over a settlement and solving the siege from above, this is the most consequential departure.
Keep the feature you refuse to lose
- Horde pressure: Choose Age of Darkness: Final Stand for fantasy Survival and a last-stand focus.
- Kingdom management: Choose Diplomacy Is Not an Option for medieval castle defense tied to governing a kingdom.
- Frontier economy: Choose Border Pioneer for the most explicit combination of colony simulation, economy, and wave-based sieges.
- Fortress construction: Choose Cataclismo for castle building and Roguelite horde defense.
- Hands-on combat: Choose The Riftbreaker when fighting beside the base matters as much as preparing it.
The best games like They Are Billions don't merely place a base beside a horde; they make preparation carry consequences. Pick the one that keeps your preferred pressure—management, construction, escalation, or action—on the defensive line, and skip any hybrid that moves it elsewhere.
