Bloons Tower Defense

Bloons TD 6 sells on Steam in 2026 with an overwhelmingly positive rating and a live content calendar. It started as a free Flash game with one road, five towers and fifty waves of balloons, uploaded to a handful of browser portals in August 2007 by a two-person New Zealand studio that had been in business for less than eighteen months. Reviewing the original today means judging that starting point on its own terms — not the nineteen years of sequels it happened to set in motion.

From carnival toy to tower defense

Ninja Kiwi was founded in Auckland in 2006 by brothers Chris and Stephen Harris, and their first real hit wasn't a tower defense game at all — it was Bloons, a dart-throwing carnival toy where the object was simply to pop as many balloons as possible, released earlier in 2007. Bloons Tower Defense followed within months, and its central idea was less an invention than a combination: the maze-and-lane tower defense format had already been popularised earlier that same year by Paul Preece's Desktop Tower Defense, and Ninja Kiwi's contribution was recognising that the cast of their existing balloon-popping toy — the bloons themselves, and a roster of dart- and tack-throwing monkeys — mapped cleanly onto that format's need for waves of enemies and a row of shooting towers. It's a smart piece of reuse rather than a mechanical breakthrough, and the review has to be honest about which of those two things it actually is.

Five towers, one road, fifty rounds

The design is about as unadorned as the tower-defense format gets. There is a single track, no difficulty selection, and a starting stake of $650 to defend forty lives across fifty rounds. Five tower types do all the work: the Dart Monkey, Tack Shooter, Ice Tower, Bomb Tower and Super Monkey, all of which are still recognisable, under close to their original names, in Bloons TD 6 today. Bloons themselves climb through a short colour ladder that tops out at black and white bloons, each of which splits into a pair of yellow bloons on death — there is no MOAB-class bloon, no camouflage, no regrowth mechanic, none of the tension-management tools later entries built entire rounds around. Popping a wave down to nothing and banking the cash to buy the next upgrade is the entire loop, repeated fifty times on one layout.

Upgrade paths exist for every tower, but they're narrow — two or three tiers of a single improving stat, occasionally branching into a special late upgrade like the Tack Shooter's ring of fire, rather than the forked, build-defining trees the series introduced almost immediately afterward. For a first attempt at the genre, built in what was presumably a short window to capitalise on the popularity of the original Bloons, that's a reasonable scope. Measured against what tower defense as a genre was already capable of in 2007, it's thin.

Funded like a 2007 portal game, because it was one

There's no monetisation story to dig into here beyond the ordinary one: Bloons Tower Defense was free, syndicated across multiple Flash portals — Newgrounds among them, where it was uploaded under Ninja Kiwi's account, frontpaged, and drew a strongly positive score from several thousand votes — plus Ninja Kiwi's own site and other portals of the era, all running the same swf and splitting ad revenue rather than one portal buying an exclusive lock on it. That's worth stating plainly because it's the opposite of how the franchise makes money now: no premium currency, no IAP, no gated content. The free-to-play mobile economy that later funded Ninja Kiwi's growth (NK Coins, premium deluxe editions) didn't exist yet, and the game is better for its absence — what you see in round one is everything the game has to offer, for as long as you care to keep playing it.

Superseded by its own sequel

The single hardest fact working against this review's score is that Ninja Kiwi's own catalogue makes the case against the original better than any outside critic could. Bloons Tower Defense 2 shipped roughly two months after this one, in October 2007, with more towers, more maps and a difficulty curve the original simply doesn't have. Every subsequent entry treated the first game's structure — one map, no modes, a handful of shallow upgrades — as a starting sketch to be redrawn rather than a foundation to build directly on top of. That's not a criticism unique to this review; it's the plain shape of the franchise's own release history, and it means the replayability question mostly answers itself. There is very little reason, on the game's own merits, to return to this version once you've seen all fifty rounds a single time.

Is it playable today?

The original Flash version cannot run natively in a browser since Adobe ended Flash Player support in January 2021, but the game hasn't disappeared. Ninja Kiwi maintains its own archive of legacy titles, and BlueMaxima's Flashpoint preserves it alongside the rest of the early series. Third-party portals including CrazyGames run it through Ruffle, the open-source Flash emulator, and as of this writing (checked 5 September 2026) that page loads and plays; Armor Games' own in-house emulator, by contrast, failed to load the game when checked the same day. Games from 2007 were typically built in ActionScript 2 rather than the ActionScript 3 that later, more technically ambitious Bloons TD entries moved to, and Ruffle's AS2 support is considerably more mature than its AS3 support — which is a reasonable, if not fully confirmed, explanation for why this particular entry in the series tends to fare better under emulation than Bloons TD 3 or 5 do. No online leaderboard or server-dependent feature was ever part of this version, so unlike some Flash-era games, nothing about it was lost when its original hosts went offline — there was simply never anything server-side to lose.

Final verdict

Bloons Tower Defense earns its place in any Flash-preservation library for what it started, not for what it is to sit down and play in 2026. The theme-to-mechanic fit — turning an existing balloon-popping toy's cast into a tower defense roster — was a genuinely good idea, executed with enough competence that its five towers survived, largely unchanged in concept, all the way to the franchise's current Steam release. But the game itself is a single map, a handful of shallow upgrades and fifty rounds you'll clear in well under an hour, superseded by Ninja Kiwi's own sequel before most players would have had a second reason to load it again. A 6.0 reflects a solid, historically important debut that its own franchise made obsolete almost immediately.