Xeno Tactic

Halfway through a comfortable run of Xeno Tactic, a wave arrives that ignores the elaborate corridor you spent ten minutes building and flies straight over the top of it. That moment is the game's central lesson, and it arrives early enough that everything after it is played differently. The maze you construct on the ground is only half a defence — the aliens come in two kinds, and a layout that answers one of them is not an answer to the other.

From Custom Maps to the Browser

Credited to Antebios, Xeno Tactic belongs to the first wave of Flash tower defense, made when the genre had barely escaped the Warcraft III custom map scene that produced it. It shows in the presentation: a plain top-down grid, functional sci-fi turret icons, an interface that assumes you already know what a tower is. It also shows in the design, which kept the part of those custom maps that made them addictive — freeform building on open terrain rather than a fixed track — at a time when most browser imitators had simplified that away.

Building Terrain Out of Turrets

Aliens spawn at an entry point and walk toward your base, taking whatever route is shortest. Your turrets are solid obstacles, so the ground path is whatever you leave open. Wall off the direct line and the swarm turns; wall off that and it turns again. What you are really constructing is a corridor with your guns on both sides of it, and the difference between a run that stalls at wave ten and one that goes deep is usually how many seconds the walk takes.

The game will not let you cut the route entirely. Seal every opening and the placement is rejected, because a fully blocked base would make the whole thing trivial. Within that limit, the standard approach is a serpentine: long parallel lanes folded back on each other, with a dense block of towers in the middle covering three or four passes of the same enemy.

Controls

Left-click to place towers from the build menu, and click a placed turret to upgrade or sell it.

Two Kinds of Enemy, Two Kinds of Defence

Ground waves obey your maze. Air waves do not — flyers cross the map in a straight line from spawn to base, so every turn you built for them is wasted, and the only thing that matters is how much anti-air fire sits under that line.

This is what forces you to plan for both at once. A defence of pure short-range ground turrets will be beautiful and useless the first time flyers appear. A defence built entirely around missile towers that engage air handles those waves fine and then bleeds lives to the ground swarms it kills too slowly. The build that survives puts anti-air capability along the direct route between the spawn and your base — the diagonal your maze does not use — while the cheap rapid-fire turrets line the corridor itself.

Watch the wave indicator. The game tells you what is coming next, and the gap between waves is your chance to sell a turret you no longer need and rebuild for the type that is about to arrive.

Build Order Advice

• Open with cheap turrets and a long path. Early waves die to almost anything, so spend those first minutes shaping the route rather than buying power you do not need yet.
• Upgrade in clusters. One heavily upgraded turret covering the elbow of a corridor outperforms four basic ones spread evenly along a straight.
• Keep a reserve. Being caught with no money when a tougher wave arrives is the most common way a run collapses, and interest on unspent cash is not a mechanic you can lean on here.
• Sell without sentiment. Refunds are partial, but a turret in the wrong place is worth less than the partial refund plus a correct placement.
• Place slowing effects at the corridor entrance. Enemies held at the start of a long path spend the whole path under fire, rather than being slowed after most of your guns have already had their turn.

Frequently Asked Questions

Who developed Xeno Tactic? It is credited to Antebios, and its popularity led to a follow-up that expanded the map and turret selection.

Why do some aliens ignore my maze? Those are the air waves. Flyers travel directly from the spawn point to your base and are unaffected by anything you build on the ground, so they need turrets that can shoot upward positioned along that straight line.

Can I completely wall off the aliens? No. The game requires a walkable route to your base and blocks any placement that would close the last opening.

Is it better to spread turrets along the path or bunch them together? Bunch them. Overlapping fire on a folded section of corridor kills far more than the same turrets spaced out, because each enemy passes the same cluster several times.

What happens when aliens reach my base? You lose lives from a fixed pool. Running that pool out ends the run, so a few leaks are survivable but a whole wave getting through generally is not.