The Legend of Bum-Bo

The Legend of Bum-Bo is Edmund McMillen's prequel to The Binding of Isaac, built around a character glimpsed only as an item in the original game — a young Bum-Bo, on a quest to recover a stolen coin, years before Isaac's own story begins. Rather than repeat Isaac's real-time bullet-hell formula, Bum-Bo rebuilds the same iconography — familiar bosses, familiar item logic, the same gleefully grotesque cartoon horror — around a match-based puzzle system: clear groups of coloured tiles to power a deck of items and spells, in isometric dioramas that look like they were built out of cardboard and construction paper. It's a genuinely different game rather than a reskin, and on Steam today it sits at Very Positive across more than 5,600 reviews. Getting there took a year longer than it should have.

A puzzle roguelike wearing Isaac's skin

The core loop swaps Isaac's twin-stick combat for tile-matching: clearing four or more same-coloured tiles in a grid triggers attacks, resource gains or item effects, and runs are built around assembling a deck of Isaac-flavoured items and spells that modify how those matches pay off. It's a legitimately different genre wearing a familiar coat of paint, and reviewers who came in expecting Isaac-with-a-different-camera generally credit it for not just being that — the match-and-deck interplay has its own rhythm, and random room layouts plus a wide item pool give runs enough variety to reward repeated attempts. The recurring criticism on the mechanical side is narrower: several reviewers, including some with 40-plus hours logged, describe the loop as eventually repetitive, and a few specifically miss the tighter moment-to-moment tension of Isaac's real-time combat. That's a fair genre-preference complaint rather than a design flaw, and it coexists in the same review corpus as plenty of players who prefer the puzzle framing outright.

A launch its own reviews call unfinished

What actually dominates the game's launch-week reception isn't the puzzle design at all. The highest-voted reviews from November 2019 read like a checklist of things a finished game is expected to have and this one didn't: no volume or audio settings menu at all, no controller support, and — most seriously for a roguelike meant to be played in short sessions — no way to save progress mid-run. Layered on top were reported game-breaking bugs, from rooms that couldn't be cleared to enemies attacking through obstacles. More than one launch-week review explicitly uses the phrase "early access" to describe the state of a game that was sold as a full release, and the pattern repeats across dozens of independent reviews rather than clustering around one bad build — evidence this was a genuine, widely-experienced launch condition rather than a handful of unlucky configurations.

The silence, the apology, and the update that fixed it

Updates continued in small doses through December 2019 and then went almost completely quiet. Reviews logged well over a year after release — one from January 2021 explicitly notes "it's been over a year since its release, and it is still a buggy mess" — show players were still experiencing the same launch-era problems long after most developers would have patched them out. In November 2020, Edmund McMillen broke that silence with a public apology on Steam for what he described as the game's "lack of transparency and seemingly abandoning the project," alongside The Lost Expansion: a free update adding a new playable character (The Lost), a new tile type, three new bosses, more than ten new unlockable items, improved audio, and — directly answering the single loudest launch complaint — the ability to save and resume a run in progress.

That update is the actual hinge point in this game's story. The Very Positive aggregate this review cites reflects a corpus built substantially from post-2020 reviews describing a functional, content-complete puzzle roguelike; the "sold as finished, shipped unfinished" complaints are concentrated almost entirely in the November-December 2019 window. A review of this game written in 2026 that only looked at the current aggregate score would miss the most important fact about it: the number is real, but it describes a game that took a year and a public apology to become the one people are actually rating.

A spin-off carrying a hard act to follow

Part of why the launch state drew as much anger as it did is context this review shouldn't skip: The Binding of Isaac: Rebirth and its Afterbirth/Repentance expansions are among the most content-dense, tightly balanced roguelikes on the market, built and refined over the better part of a decade with community modding and years of live patches feeding back into the design. Bum-Bo arrived as a new game in a different genre from the same solo-adjacent creative team, without that decade of iteration behind it, and got measured against Isaac's own standard anyway — fairly, since it was sold at a comparable price point with comparable production values implied, but it's still a much higher bar than most puzzle-roguelike debuts get held to. Some of the "lacks depth" complaints in the review corpus read less like a flaw specific to Bum-Bo and more like the inevitable comparison tax of following up one of the genre's most thoroughly refined games with something built from scratch in a different mould.

Verdict

The Legend of Bum-Bo, played today, is a legitimately inventive puzzle-roguelike take on Isaac's world with distinctive art direction and enough item variety to reward repeated runs — and it's worth judging on that version rather than the one that shipped in November 2019 with no save function and no volume slider. The launch was a real, well-documented failure to ship a finished product at full price, and the year of near-silence that followed was worse than the bugs themselves. That McMillen eventually fixed it properly, in public, with a substantial free expansion rather than a quiet patch, is the reason this review can recommend the game in good conscience rather than merely noting that its score eventually recovered.